Valorization of Sour Cherry Seeds in Beef Meatballs: Effect on Quality, Lipid Oxidation, Texture Profile, Acrylamide Formation and Antioxidant Activity

TL;DR

Adding sour cherry seed powder to beef meatballs improves their quality by reducing harmful compounds and enhancing antioxidant properties.

Contribution

This study demonstrates the use of sour cherry seed powder as a sustainable ingredient to improve meatball quality and safety.

Findings

Adding 1% sour cherry seed powder reduced acrylamide and lipid oxidation in meatballs.

Sour cherry seed powder increased total phenolic content and antioxidant activity.

Cooking temperature significantly affected most quality parameters of meatballs.

Abstract

In the study, the effects of adding sour cheery seed powder at different concentrations (0%, 0.5%, 1%, and 1.5%) on the pH, water content, lipid oxidation, cooking loss, color, TPC, antioxidant activity (DPPH and ABTS), texture, and acrylamide contents of meatballs cooked at 150 °C, 200 °C, and 250 °C were investigated. The sour cherry seed powder significantly affected the pH, cooking loss, a*, b*, C*, h°, TBARS, acrylamide, hardness, and springiness, while no significant effect was found on the moisture, L*, cohesiveness, gumminess, or chewiness. The cooking temperature had a significant effect on all the parameters except cohesiveness, gumminess and chewiness. The addition of 1% sour cherry seed powder resulted in the lowest acrylamide and TBARS values. The sour cherry seed powder increased the total phenolic content (TPC) and antioxidant activity of the meatballs. These results indicate that sour cherry seed powder can be used as a sustainable food ingredient in meatball production, reducing acrylamide and lipid oxidation while improving the antioxidant capacity, color, and texture properties.

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1. Introduction

Meat holds a significant place in nutrition among animal-derived foods due to its macro and micro components. Furthermore, it has a higher bioavailability compared to plant-based foods. Meatballs, in particular, stand out among meat products due to their ease of use, practical preparation, sensory properties (including stickiness, chewability, and elasticity), and economic value [1,2,3,4]. Beef meatballs are principally composed of minced meat, with the inclusion of various additional components in their preparation (spices, salt, fat, etc.) [5].

The process of cooking is of fundamental importance in the development of sensory qualities, such as flavor, aroma, and texture, especially in meat products. In addition, it is a crucial step in ensuring the microbiological safety of food. Cooking processes applied to meat and meat products denature the proteins and cause changes in the collagen structure of the meat. This softens the meat’s texture, increasing its edibility [6,7]. However, this process is not limited to acquiring desired characteristics; in addition to some beneficial changes in the food, negative consequences, such as quality loss or the formation of undesirable compounds, can also occur during cooking [7]. In this respect, one of the undesirable food contaminants resulting from cooking is acrylamide (ACR).

Acrylamide (ACR) is an unsaturated amide molecule that enters the body through food consumption by living organisms. Many parameters influence ACR formation, including the raw materials, heat treatment (type and duration), and pH [8]. Acrylamide causes diseases in animals (cancer) and humans (neurotoxic effects). Studies have reported that the consumption of acrylamide in food causes tumors in organs (intestines, breasts, and kidneys) [9,10]. The International Agency for Cancer Research classifies it as a Group 2A carcinogen, meaning it is a “probable human carcinogen” [11]. However, the cooking process also carries the concern of acrylamide formation. In fact, acrylamide does not occur naturally in food sources. The formation of this compound is a consequence of the reaction between the sugars and amino acids in carbohydrate- and protein-rich foods due to high temperatures [12]. Considering a body weight of 40 kg, daily acrylamide intake can be calculated as 0.66 μg/kg body weight/day [13]. During production, the estimated exposure to ACR is 0.07 mg/kg/day [9,14]. In the literature, phytochemicals, phenolic compounds in many fruits and vegetables, have been found to reduce acrylamide-induced toxicity. This is mainly due to the antioxidant properties of phytochemicals and their ability to control intracellular signal transduction and scavenging free radicals and reduce oxidative stress damage [15]. Therefore, adding antioxidants to meat products may be an effective method to prevent or slow down oxidative reactions [16,17,18]. Antioxidants are defined as substances that are capable of delaying or preventing the oxidation of other molecules, even at low concentrations. These substances work through various mechanisms to stop the formation of radicals and create more stable products; thus, they can extend the shelf life of meat-based foods by preserving their quality. Natural antioxidants, such as polyphenols found in seeds, have the potential to provide this protective effect [19].

The term “functional food” is often used to describe sour cherries due to their high antioxidant content. The anthocyanins obtained from sour cherries have strong antioxidant and anti-inflammatory activities. Furthermore, it has been found that sour cherries reduce the formation of HAAs in meat products and improve their nutritional quality. Sour cherry seeds, however, are discarded as waste [20]. Nevertheless, scientific research has indicated that the seeds contain substantial levels of phytochemicals [21]. The aim of waste utilization is not only to alleviate the waste load in landfills but also to enable producers to support a sustainable economy [22]. Sour cherry seed protein is a non-toxic, plant-based food protein rich in essential amino acids [23]. In this context, innovative ways to reduce acrylamide formation in food through waste utilization need to be found.

Specifically, this research explores the use of sour cherry seed powder, which is considered waste, in beef meatball production. It is envisioned that this will provide an economic benefit from using sour cherry seed powder, which possesses high antioxidant activity. To the best of our knowledge, there is an absence of research in the existing literature evaluating the acrylamide levels of meatballs produced using sour cherry seed powder. Furthermore, this research evaluates the effects of varying concentrations of sour cherry seed powder on various quality parameters (pH, moisture, and color), lipid oxidation, texture profile, and antioxidant activity of meatballs.

2. Materials and Methods

2.1. Preparation of Meatballs

The meat and intermuscular fat used in the study were sourced from a local butcher. Initially, the beef meat was stripped of visible fat and connective tissue and then ground into minced meat. Then, it was adjusted to a 15% fat content. The meatball samples, containing 15% fat, were initially separated into four batches. The first batch consisted of beef meatball dough without sour cherry seed powder, the second batch consisted of meatball dough containing 0.5%, the third batch contained 1% and, finally, the fourth batch contained 1.5% sour cherry seed powder. Thereafter, the meatballs were shaped using a ready-made steel globe mold with dimension of 7 × 1 cm to ensure that the meatballs were uniform in size and shape. The meatballs were prepared in portions of approximately 50 g. The meatballs were rested for a period of 6 h (4 °C) prior to the commencement of the shaping process.

2.2. Preparation of Sour Cherry Seed Powder

Montmorency (Prunus cerasus L.) sour cherries were harvested at full ripeness in July 2025 from Göllü Village (Erzurum, Türkiye). Once the sour cherry seeds were manually separated, the samples were dried in a laboratory-type lyophilizer (Martin Christ, Alpha 1-2 LD, Osterode am Harz, Germany) at −56 °C under a vacuum pressure of 0.9 mbar for approximately 24 h until a constant weight was achieved. The lyophilized seeds were ground into powder using a laboratory grinder (TB200, Mıza, Kunshan, China) and passed through a sieve with a 500 µm pore size to obtain a homogeneous particle size. The sour cherry seed powder was stored in a glass shot bottle at −20 °C until the analyses were performed. The prepared sour cherry seed powder was added to the meatball formulations at specified ratios (% w/w), and a control group without sour cherry seed powder was also prepared for comparison.

2.3. Cooking Conditions

The cooking process on a hotplate (WiseTherm HP-LP-C-P, Daihan Scientific, Wonju, South of Korea) was conducted without the use of fat or oil. The hotplate surface temperature was adjusted to 150 °C, 200 °C, and 250 °C, respectively, using a laboratory thermometer (Digital Food Thermometer, İstanbul, Türkiye) prior to initiating the cooking process. The meatballs were subjected to a cooking time of 10 min, with 5 min allocated for the first phase and a further 5 min allocated for the second phase.

2.4. Chemicals and Reagents

All chemicals and reagents, including FCR (Folin–Ciocalteu reagent, 2 N), gallic acid (anhydrous), DPPH (2,2-diphenyl-1-picrylhydrazyl), ABTS (2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid), ≥98% HPLC), potassium persulfate (≥99%), sodium carbonate (≥99.5% ACS reagent), sodium acetate (≥99% ACS reagent), Trolox (6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid), propyl gallate (≥98% HPLC grade) 2-thiobarbituric acid (≥98%), trichloroacetic acid (ACS reagent), ethylenediaminetetraacetic acid disodium salt dihydrate (99.0–101.0% ACS reagent), 1,1,3,3-tetramethoxypropane (99%), acrylamide analytical standard, ortho-phosphoric acid (≥85%), glacial acetic acid (100% anhydrous), acetonitrile (≥99.9% HPLC grade), methanol (≥99.9% HPLC grade), Carrez I solution, and Carrez II solution were purchased from Sigma (St. Louis, MO, USA) and Merck (Darmstadt, Germany).

2.5. pH Value

The pH analysis of the samples was performed by means of a pH meter (Mettler Toledo, Greifensee, Switzerland) as described by [24]. A total of 10 g of homogenized meatball and sour cherry seed powder samples were added to a beaker containing 100 mL of distilled water. The samples were homogenized with an ultraturrax (IKA ®T18 digital ULTRA-TURRAX®, Staufen, Germany) for 1 min and measurements were taken.

2.6. Moisture Content

The moisture content of the meatballs was determined in accordance with the methodology outlined by [25].

2.7. Cooking Loss Assay

The determination of cooking loss values was conducted by means of weight measurement prior to and following the cooking process, as outlined by [24].

2.8. Color Value

The color characteristics of the samples were determined using a Konica Minolta Colorimeter (Chroma Meter, CR-210, Minolta, Osaka, Japan). L* represents the lightness/brightness, a* represents red–green, b* represents yellow–blue, C* is the color intensity, and h° is the hue [26,27,28].

2.9. Acrylamide Analysis

The acrylamide levels present in the meatball samples were determined in concordance with the methodology delineated by [29]. The analysis was conducted in the following manner: A quantity of 0.1 mL of Carez I, 0.1 mL of Carez II, and a mixture containing 9.8 mL of acetic acid (c = 0.2 mM) were added to 1 g of the sample, after which the mixture was agitated for a period of 2 min. Subsequently, the samples were subjected to a centrifugal process at a speed of 500 revolutions per minute for a duration of 10 min. Subsequent to filtration through a 0.45 µm syringe filter, the HPLC procedure was initiated. The flow rate of the experiment was maintained at 1 mL/min using a THERMO-Acclaim™ 120-C18 (Waltham, MA, USA) column (3 µm, 120 Å, 4.6 × 150 mm), with a detector set to 206–400 nm and a column temperature of 36 °C. The limit of detection (LOD) was calculated as 0.031195 ng/µL, and the limit of quantification (LOQ) as 0.09453 ng/µL. A calibration curve was constructed using acrylamide standard solutions, and the regression analysis revealed a linear equation of y = 72.138x − 0.2871, with a regression coefficient of R^2^ = 1.

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2.10. Lipid Oxidation Assay

The extent of lipid oxidation in the beef was determined by a TBARS assay, based on the methodology of [30] with minor adjustments. The absorbance was measured at 532 nm using a UV–Vis spectrophotometer (UVmini-1240, Shimadzu, Kyoto, Japan).

2.11. Texture Profile Assay

The textural characteristics were evaluated by applying a texture profile analysis following the procedures described by [31]. Measurements of hardness (N), springiness, cohesiveness, gumminess (N), and chewiness (N·mm) were obtained using a TA.XT Plus texture analyzer (Stable Micro Systems, Godalming, UK) fitted with a 5 kg load cell. The meat samples were prepared as uniform cubes and subjected to a double compression test to 50% of their initial height using a cylindrical probe with a 36 mm diameter (SMS P/36). The probe speed was set at 2 mm/min prior to compression, reduced to 1 mm/min during the test, and returned to 1 mm/min after compression. All the analyses were carried out at ambient temperature (25 °C) using the instrument’s texture analysis software.

2.12. Preparation of Meatball Samples for Antioxidant Activity Analysis

According to Wang et al. [32], the extraction of antioxidant compounds from the meatballs was achieved by means of the following procedure. The initial step involved the meticulous weighing of the samples at precisely 2.5 g, ensuring accuracy of measurements. These samples were then subjected to a rigorous homogenization process using an Ultra-Turrax homogenizer (T25 digital, IKA, Staufen, Germany), operating at an elevated speed of 8000 rpm for a duration of two minutes. Following homogenization, 25 mL of 70% (v/v) methanol was added to the samples, and the mixture was subjected to extraction for 1 h at 25 °C in a shaking incubator at 100 rpm. Subsequent to the extraction process, the mixture was subjected to centrifugation (Heal Force, Shanghai, China) at 4000× g for a duration of 10 min. The resultant material obtained following centrifugation was filtered using Whatman No. 1(FILTER PAPERS, 125 mm, ISOLAB, Geffen, The Netherlands) filter paper, after which the samples were stored at −20 °C until the subsequent analysis stage.

2.13. Measurement of Total Phenolic Content (TPC)

The total phenolic content (TPC) of the meatball samples was determined based on the method described by [21,28], with some minor modifications. For the TPC analysis, 15 µL of extract solution was mixed with 112.5 µL of Folin–Ciocalteu reagent diluted 1:10 (v:v), and the mixture was vortexed for 30 s. The mixture was then left to stand in the dark at 25 °C for 5 min. At the end of this period, 112.5 µL of 6% Na_2_CO_3_ was added, and the samples were again incubated at 25 °C in the dark for 60 min. After incubation, the absorbance values were measured at a wavelength of 765 nm using an ELISA microplate reader (Thermo Fisher Scientific, Waltham, MA, USA). A calibration curve consisting of eight different concentrations ranging from 0.01 to 0.4 mg/mL was prepared for gallic acid. The results obtained were expressed as mg gallic acid equivalent (GAE) per gram of sample.

2.14. DPPH Radical Scavenging Activity

The DPPH radical scavenging activity of meatball samples was determined using the method described by [21,28,33]. Briefly, 100 µL of extract solution was added to 2 mL of a 0.1 mM DPPH solution prepared in methanol. The reaction mixture was incubated for 30 min at room temperature in the dark. The absorbance was measured at 517 nm using an ELISA microplate reader (Thermo Fisher Scientific, Waltham, MA, USA). The calibration curve for Trolox was constructed using six levels in the range of 0.025 to 1.25 mM. The DPPH radical scavenging activity was calculated as µmol Trolox equivalents (TE) per gram of sample.

2.15. ABTS Radical Scavenging Activity

The ABTS radical scavenging activity of meatball samples was determined using the method described by [28], with some minor modifications. For this purpose, a solution containing 7 mM ABTS and prepared with 2.45 mM potassium persulfate (K_2_S_2_O_8_) was incubated at room temperature and in the dark for 12–16 h. Separately, a 20 mM sodium acetate (C_2_H_3_NaO_2_) solution was adjusted to pH 4.5 using 0.1 mol/L HCl. The prepared ABTS solution was diluted with the sodium acetate to obtain an absorbance of 0.700 ± 0.01 at 734 nm. To assess the radical scavenging activity, 10 μL of meatball sample was mixed with 200 μL of the ABTS solution and incubated for 6 min. At the end of the incubation period, the absorbance was measured at 734 nm using an ELISA microplate reader (Thermo Fisher Scientific, Waltham, MA, USA). The calibration curve for Trolox was constructed using nine levels in the range of 0.025 to 1.25 mM. The ABTS radical scavenging activity was calculated as µmol Trolox equivalents (TE) per gram of sample.

2.16. Statistical Analysis

The experiment was designed with four concentrations (0%, 0.5%, 1%, and 1.5%) and three cooking temperatures (150 °C, 200 °C, and 250 °C). The data obtained were subjected to a statistical analysis of variance (ANOVA) using GraphPad Prism 9 and IBM SPSS Statistics 25, with Duncan’s Multiple Comparison Test employed to derive the mean values for significant sources of variation. Significance levels were defined as * p < 0.05, ** p < 0.01, and *** p < 0.001. Tukey’s post hoc tests were applied to determine significant differences between groups at a 0.05 confidence level. A principal component analysis (PCA) was performed using SIMCA 14.1 (Umetrics, Umea, Sweden) to evaluate the homogeneity and correlations of the characteristics of the meatball samples. The experiments were performed in duplicate and the analyses in triplicate (n = 3).

3. Results

3.1. Data on Meat and Sour Cherry Seed Powder

The pH, moisture, TBARS, and color values of the beef meat used as the raw material in the study are given in Table 1. The research data are consistent with other previously reported studies [6,24,34,35]. On the other hand, there may be differences between studies. In particular, these differences may vary depending on many factors, such as the type of muscle used, the breed of cattle, and the feeding conditions. The study also presents the pH, color, TPC, DPPH, and ABTS results of sour cherry seed powder used in meatball production (Table 1).

3.2. pH Results

Table 2 shows the pH, moisture, and cooking loss results for the cooked meatballs with and without sour cherry seed powder. Following a comprehensive analysis of the data, it was determined that the ratio of sour cherry seed powder and the temperature at which it was cooked had a considerable influence on the pH levels (p < 0.01). The highest pH value was found in the control group, while a decrease in the pH was observed in the samples to which sour cherry seed powder was added. Furthermore, it was indicated that the pH values of the samples decreased as the cooking temperature increased. However, it was determined that the average pH value of raw meatballs was 5.86 and that it increased with the cooking temperature. Specifically, it has been stated that this increase is related to the release of bonds containing sulfhydryl, imidazole, and hydroxyl groups during cooking [2,36]. Similarly, Savaş et al. (2023) also reported a decrease in the pH values of meatball samples with different amounts of sumac added, finding statistically meaningful disparities among the samples [24]. Elbir and colleagues, in their study, determined that the use of different amounts of chia powder caused differences in the pH values of meatballs, while reporting that the cooking temperature did not have an important impact on the samples [6].

3.3. Moisture Content (%)

It was observed that using different proportions of sour cherry seed powder did not exert a substantial influence on the moisture content (p > 0.05). The moisture levels of the samples ranged from 57.32% to 59.45%. Conversely, it was observed that the cooking temperature exhibited a significant impact on the moisture content of the meatballs. As the cooking temperature increased, the moisture content of the samples decreased. Specifically, such decline has been attributed to the shrinkage in the myofibrillar proteins and perimysial connective tissue that occurs during the cooking process [37]. Bulan and Oz determined that the tarragon ratio did not significantly affect the moisture level of meatball samples in their study [38]. Furthermore, it was indicated that the cooking temperature had a significant impact on the moisture content of the samples. Similarly, Serdaroğlu detected that the moisture level of cooked meatball samples varied between 56.1% and 64.7% [39]. Indeed, the differences observed in the moisture content are influenced by various parameters, such as the cooking temperature and time, cooking conditions, and muscle type.

The cooking process is crucial for the edibility of meat. Indeed, the cooking process directly affects various parameters of the meat, such as juiciness and tenderness, as well as its sensory characteristics. It has been stated that cooking meat causes protein denaturation and shrinkage of myofibrils and collagen proteins [40].

3.4. Cooking Loss (%)

The cooking loss values of the samples were determined from the changes in their weights before and after cooking. When the cooking loss results were examined, it was observed that the sour cherry seed powder ratio and cooking temperature had a significant impact on the samples (p < 0.01). The cooking loss values of the meatballs ranged from 41.06% to 47.72%, and the highest cooking loss value was observed in the samples with 1% sour cherry seed powder added. However, it was detected that the cooking loss values depending on the cooking temperature were highest in the sample group cooked at 250 °C. Mudalal and colleagues indicated that the cooking loss values of meatballs ranged from 35.68 to 39.37% in their study [41]. Indeed, the disparities observed among the studies can be attributed to a multitude of factors, including the pH, water content, fat content, cooking processes (temperature, time), and the specific muscle type of the meat.

3.5. Color Values

The results pertaining to the color parameters, a pivotal factor influencing consumer preferences, are elucidated in Table 2 [42].

3.5.1. Lightness (L*)

It was determined that the utilization of varying ratios of sour cherry seed powder did not exert a significant influence on the L* values of the samples. The L* parameters of the samples exhibited a fluctuation between 34.40 and 36.62, with the maximum L* value being recorded in the sample group that had the addition of 0.5% sour cherry seed powder. Conversely, it was established that the cooking temperature exerted a substantial influence on the L* values of the meatball samples (p < 0.01) (Table 2). The greatest L* value was identified in sample group that was cooked at 150 °C, and it was determined that the L* value decreased as the cooking temperature increased. Indeed, it has been stated that the decrease in L* values is essentially due to the browning reactions caused by cooking [41]. It has also been stated that it is related to modifications occurring in the heme proteins [43]. Mudalal and colleagues determined that the L* value of their beef meatballs was 43.78 after cooking [41]. Savaş detected that the addition of varying rates of spices resulted in the L* values of their meatball samples ranging from 29.04 to 34.01 [2].

3.5.2. Redness–Greenness (a*)

It was determined that the a* values of the meatballs ranged from 7.44 to 8.59 and were significantly affected by the sour cherry seed powder ratio (p < 0.05). The highest a* level was detected in the sample group with 1.5% sour cherry seed powder added. In contrast, it was observed that the cooking temperature had a substantial impact on the a* values of the meatballs, with a decrease in the a* value as the cooking temperature increased. Savaş reported that the a* levels of their samples decreased as the cooking temperature increased and that the a* values of the samples ranged from 3.63 to 5.46 [2].

Aminzare and colleagues describe grape seed as an important natural antioxidant source that can prevent color loss in meat products. According to these researchers, cooked sausages produced using grape seed powder maintained higher redness (a*) values compared to nitrite-containing control sausages over 40 days of storage at 4 °C. In a similar manner, it has been ascertained that the incorporation of grape extract is concomitant with the maintenance of red color in fermented and dry-cured sausages [44].

Aquilani and colleagues found that the use of commercial grape seed extract (in powder form, 10 g/kg) resulted in redness values at the end of the maturation process that were comparable to those of nitrite-containing control products [45]. Similarly, Pateiro and colleagues reported that in dry-cured sausages produced with the addition of freeze-dried hydroethanolic grape extract at a level of 200 mg/kg, the red color was similarly preserved throughout both the maturation and storage periods [46].

3.5.3. Yellowness–Blueness (b*)

The proportion of sour cherry seed powder and cooking temperature significantly affected the b* values of the samples. The b* values of the samples ranged from 6.84 to 8.93. The highest b* value was observed in the samples with 1.5% sour cherry seed powder added (Table 2). In addition, it was noted that the b* value decreased in proportion to the increase in cooking temperature. Indeed, previous studies in the literature have reported similar results [2].

3.5.4. Chroma (C*) and Hue (h°)

The proportion of sour cherry seed powder, in conjunction with the temperature during the cooking process, exerted a substantial influence on the C* and hº values of the samples. The C* and hº values of the samples ranged from 10.16 to 12.41 and 41.35 to 46.17, respectively. The greatest C* and hº values were ascertained in the sample group with 1.5% sour cherry seed powder added. Conversely, an inverse correlation was observed between the C* and hº values and the cooking temperature (Table 2).

3.6. Acrylamide

The results pertaining to the acrylamide and TBARS contents of the meatball samples are presented in Table 3. It was found that the acrylamide content of the samples was significantly influenced by the proportions of sour cherry seed powder utilized and the temperature of the cooking process (p < 0.01). The acrylamide content of samples was observed to range from 51.44 to 59.35 µg/kg. The lowest acrylamide level was found in the sample group with 1% sour cherry seed powder added (Table 3). The study found that the addition of sour cherry seed powder resulted in a decline in the acrylamide levels. Indeed, such a decline is thought to be a consequence of the high antioxidant activity of sour cherry seeds. Kaplan and colleagues reported that the acrylamide levels in different meat and food samples ranged from 20 to 250 μg/kg [47]. In their study, Eerola et al. [48] found acrylamide levels between nd and <68 μg/kg in minced meat beef, meatballs, and chicken nuggets samples. Indeed, many parameters affect acrylamide formation. It is emphasized that the applied pH, cooking conditions, and temperature are particularly influential. In addition, it has been stated that the content of product to which the cooking process is applied affects acrylamide formation [49,50,51,52]. On the other hand, the acrylamide levels increased depending on the cooking temperature, and were found to be highest in samples cooked at 250 °C. Acrylamide (ACR) formation has traditionally been attributed to the Maillard reaction, which occurs at high temperatures between amino acids and reducing sugars. Furthermore, it has been stated that lipid oxidation products, particularly acrolein, contribute significantly to ACR formation [53].

3.7. Lipid Oxidation (TBARS)

Lipid oxidation is known as one of the factors contributing to the quality of meat and meat products. The use of different ratios of sour cherry seed powder significantly influenced the TBARS levels of the samples (p < 0.05) (Table 3). The TBARS levels of the samples exhibited a variation between 0.73 and 1.04 mg MDA/kg. A decline in the TBARS values was observed in the samples as the amount of sour cherry seed powder added increased. Similarly, Savaş et al. [24] determined that the addition of sumac reduced the TBARS values of their samples and that there were statistically significant differences among the samples. They stated that this decrease was due to phenolic compounds and antioxidant capacity. On the other hand, Elbir et al. [6], in their study of meatballs cooked using different ratios of chia powder, reported that the TBARS levels of the samples exhibited a variation between 0.612 and 0.657 mg MDA/kg, and that there were no statistically significant differences among the samples. However, the cooking temperature had a significant effect on the samples (p < 0.05) (Table 3). As the cooking temperature increased, the TBARS values of the samples increased, and the highest TBARS value was determined as 1.01 mg MDA/kg at 250 °C. Altun et al. [54], reported that the TBARS values of marinated meat products varied between 0.75 and 1.21 mg MDA/kg. It is thought that the differences in the TBARS values of these samples were affected by many parameters, such as the cooking method used, temperature, time, and muscle type.

A plethora of studies have been conducted in the extant literature on the use of fruit extracts to control lipid oxidation in meat products. For example, it was determined that extracts of pomegranate peel, pomegranate seed, and kinnow peel powder reduced the TBARS values in cooked goat meat patties [55]. Grape seed extract was shown to reduce the TBARS values in both raw and cooked pork meatballs [56]. Dejong and Lanari reported that olive polyphenols reduced TBARS values by inhibiting oxidation in cooked beef and pork [57].

Furthermore, rosehip seed powder at different concentrations was shown to reduce lipid oxidation in meatballs and can be used as a natural antioxidant in cooked meatballs [58].

3.8. Texture Analysis

The texture profile analysis results of meatball samples with different proportions of sour cherry seed powder added are presented in Table 4. The results show that the proportion of sour cherry seed powder and cooking temperature had a significant impact on the hardness and springiness values, while they did not significantly affect the cohesiveness, gumminess, or chewiness values. The hardness levels of the samples ranged from 3.17 to 4.98 N, the springiness values from 0.95 to 0.99 mm, the cohesiveness values from 0.28 to 0.39, the gumminess values from 1.22 to 1.41 N, and the chewiness values from 1.19 to 1.39 N·mm (Table 4). On the other hand, when examined in terms of cooking temperature, it was determined that as the cooking temperature increased, the hardness, springiness, gumminess, and chewiness values of the samples increased, while the cohesiveness values decreased. Similarly, Su et al. [31] investigated the hardness (2409.78–3079.13 g), springiness (82.67–85.20%), cohesiveness (62.17–67.93%), gumminess (1507.18–2091.47 g), chewiness (1246.37–1742.60 g), and resilience (25.20–29.87%) values of rabbit meatballs.

Ulu detected that the hardness value of meatballs to which different processes were applied ranged from 13.3 to 28.3 N, the springiness value from 5.7 to 6.9 mm, the cohesiveness value from 0.31 to 0.43, the gumminess value from 4.5 to 11.1 N, and the chewiness value from 29.9 from 76.1 N·mm [59]. The researchers of [60] found that the hardness of meatballs with different ratios of pumpkin seed flour ranged from 103.80 to 142.39 N, the springiness from 0.48 to 0.66 mm, the cohesiveness from 0.25 to 0.32, and the chewiness from 18.13 to 23.53 N·mm. In their study, Ikhlas et al. [61] found that the hardness, cohesiveness, elasticity, and chewiness values of quail meatball samples ranged from 7.90 to 10.08 kg, 0.34 to 0.40, 10.70 to 12.15 mm, and 24.34 to 31.38 kg·mm, respectively. Bıyık and Turhan [62] determined that there were statistically significant differences in the hardness (between 114.82 and 189.49 N) and chewiness (between 40.84 and 78.26 N·mm) values of beef meatballs containing different proportions of peanut shells, while reporting no statistically significant differences in the springiness (between 0.74 and 0.86 mm) and cohesiveness (between 0.42 and 0.62). Indeed, there are differences in the research. These differences are thought to be influenced by several parameters, including the type of muscle used, the cooking processes, duration, temperature, and analysis procedures.

3.9. Total Phenolic Content (TPC)

Table S1 and Figure 1 show the total phenolic content DPPH scavenging activity and ABTS scavenging activity values obtained for the meatballs prepared using different concentrations (0%, 0.5%, 1%, and 1.5%) and cooking temperatures (150 °C, 200 °C, and 250 °C). When comparing the total phenolic content (TPC) of meatball samples based on the sour cherry seed powder concentration, the highest levels were observed in the meatballs containing 0.5% (0.20 mg GAE/g) and 1% (0.22 mg GAE/g) sour cherry seed powder (p < 0.01) (Table S1). The TPC results were evaluated based on the cooking temperature, and the TPC level of meatballs cooked at 250 °C (0.22 mg GAE/g) was found to be the highest (Table S1). The TPC values obtained at 150 °C and 200 °C were statistically similar (Table S1 and Figure 1a). Furthermore, the interaction between the cooking temperature and sour cherry seed powder addition was found to be statistically significant for the TPC (p < 0.01).

In the meatball samples cooked at 150 °C, the TPC values were found to be similar at all concentrations, while the 1.5% sample showed the highest value, exhibiting a statistically significant increase compared to the control (p < 0.001) (Figure 1a). In contrast, at 200 °C, the sample with 0.5% additive reached the highest TPC value and showed a highly significant difference compared to the control (p < 0.0001) (Figure 1a). The highest TPC value was recorded at 250 °C with the 1% sour cherry seed powder additive, which was significantly higher than both the control and the 1.5% group (p < 0.0001) (Figure 1a).

The phenolic compounds found in seeds contain different compounds that can be evaluated for enhancing the antioxidant capacity of meat products [19]. Extracts obtained from plants rich in bioactive compounds have been observed to be effective for slowing down the oxidation of fats and proteins during the storage of meat and meat products [63].

A study showed that as the proportion of mango seed increased in goat meatballs containing mango seed extract, the total phenolic content rose significantly [63]. During cooking, the oxidation rate increases due to heat application; therefore, the presence of antioxidants is crucial to prevent the oxidation of lipids and proteins [64]. The TPC of beef patties containing pomegranate seed extract (PSE) was approximately 201 mg GAE/kg when pan-fried and around 330 mg GAE/kg when oven-baked. When beef patties with PSE were cooked on charcoal, this value increased to 453 mg GAE/kg. In chicken patties, the TFC ranged from 231 to 389 mg GAE/kg in the control patties, while it reached 367 to 477 mg GAE/kg in the patties with PSE [65]. The TPC of control meatball samples was measured as 0.42 mg GAE/g. A significant increase in the TPC of the meatballs was observed with the addition of chasteberry seed powder. In particular, when 10% chasteberry seed powder was added to the formulation, the TPC increased approximately 5.5-fold. This result indicates that chasteberry seed powder can be used as a natural source of phenolic compounds in meat products such as meatballs [34].

3.10. DPPH Scavenging Activity

The DPPH scavenging activity values for the meatball samples based on the sour cherry seed powder concentration were highest in the meatballs containing 1.5% (18.28 mg TE/g) sour cherry seed powder. The DPPH scavenging activity values of meatball samples supplemented with sour cherry seed powder at 0.5% and 1% were found to be statistically similar. In terms of cooking temperature, the meatball samples cooked at 150 °C (14.70 mg TE/g) and 250 °C (14.18 mg TE/g) showed the highest DPPH radical scavenging activity values, and these values were found to be statistically significant (Table S1 and Figure 1b). Additionally, the interaction between the cooking temperature and the addition of sour cherry seed powder was found to have a statistically significant effect on the DPPH scavenging activity (p < 0.01) (Table S1).

In the meatballs subjected to a cooking temperature of 150 °C, an increase in the antioxidant activity was observed that was directly proportional to the increase in the sour cherry seed powder content. The highest recorded value of antioxidant activity was attained for a powder content of 1.5% (p < 0.0001) (Figure 1b). In contrast, at 200 °C, all concentrations exhibited similar antioxidant activity, and no significant difference was found among the groups (p > 0.05) (Figure 1b). Increasing the cooking temperature to 250 °C resulted in a renewed increase in antioxidant capacity, with the meatballs containing 1.5% sour cherry seed powder showing significantly higher activity compared to the control group (p < 0.0001) (Figure 1b).

It was observed that in goat meatballs with added mango seed extract, the DPPH antioxidant activity increased in parallel with the increase in the extract concentration [63]. Keşkekoğlu and Üren stated in their study that the DPPH of cooked meatballs with pomegranate seed extract varied depending on both the type of meat used and the cooking method, and showed a positive correlation with the TPC [65]. A study found that substituting 15% of tapioca flour with purple sweet potato flour enhances the antioxidant capacity of chicken meatballs by increasing their DPPH free radical scavenging activity without compromising their physical properties [66]. The addition of chasteberry seed powder increased the antioxidant capacity of meatballs in another study. Measurements using the DPPH scavenging activity showed that the antioxidant activity of meatballs containing chasteberry seed powder was approximately 1.9-fold higher than that of the control samples. This potent antioxidant effect was attributed to the flavonoids, tannins, iridoids, and diterpenoid compounds found in chasteberry, which inhibit lipid oxidation [34,67,68].

3.11. ABTS Scavenging Activity

The ABTS scavenging activity values for the meatball samples based on the sour cherry seed powder concentration were highest for the meatballs containing 1% (23.18 mg TE/g) sour cherry seed powder. The ABTS activity values of other meatball samples were found to be similar to each other statistically. When evaluated according to the cooking temperature, the ABTS of the meatball samples was found to be statistically different from each other. The highest ABTS activity was determined at 250 °C (28.03 mg TE/g), 200 °C (19.86 mg TE/g), and 150 °C (13.54 mg TE/g), respectively (Table S1 and Figure 1c). Additionally, the interaction between the cooking temperature and the addition of sour cherry seed powder was found to have a statistically significant effect on the ABTS scavenging activity (p < 0.01) (Table S1).

In the meatball samples cooked at 150 °C, the ABTS radical scavenging activity increased depending on the sour cherry seed powder ratio, and the highest value was determined in the group containing 1.5% sour cherry seed powder; this group was found to be statistically significantly higher compared to the control and the 1% sour cherry seed powder samples (p < 0.0001) (Figure 1c). At 200 °C, while no significant difference was observed between proximate concentrations, statistically significant differences were found between the lowest and highest concentrations (0.5–1.5% and control–1.5%) (p < 0.001) (Figure 1c). The highest ABTS activity was obtained at 250 °C, and the group with 1% sour cherry seed powder exhibited the highest antioxidant capacity among all experimental conditions and was significantly different from all other groups (p < 0.0001) (Figure 1c).

The increase in antioxidant activity in the meatball samples supplemented with sour cherry seed powder can be explained by the phenolic compounds and other bioactive substances present in the seeds. In particular, the highest levels of DPPH and ABTS activity at high concentrations (1–1.5%) are consistent with the concentration-dependent increases reported for meatball samples supplemented with mango [63], pomegranate [65], and chasteberry [34,67,68] seed extracts. The higher or lower activity of sour cherry seed powder compared to other fruit extracts may be due to factors such as the composition, availability, and bioavailability of phenolic compounds, as well as their interaction with the meat matrix and cooking conditions. At certain cooking temperatures, the preservation of phenolic compounds or the formation of new antioxidant compounds may increase activity; at low concentrations, relatively lower activity may be observed due to limited release [24].

3.12. PCA Analysis

A principal component analysis (PCA) is a descriptive method that allows for the visualization of the relationship between samples and variables [69]. As illustrated in Figure 2a–d, the score scatter plot, loading scatter plot, biplot and dendrogram principal component analysis scores and load graphs are presented for the various quality parameters, antioxidant activity, texture, lipid oxidation, and acrylamide content of meatballs prepared with different ratios of sour cherry seed powder. The first component (PC1) accounts for 44.7% of the total variation, while the second component (PC2) accounts for 18.5%. The two components collectively explain 63.2% of the total variation. As is evident from Figure 2a,d, three distinct groups can be identified. Indeed, the formation of different groups is a significant indicator of differences among the sample groups. As illustrated in Figure 2b, a multifaceted relationship among the samples is revealed, exhibiting both negative and positive correlations. Furthermore, the DPPH, L*, a*, b*, C*, h°, pH, moisture, and cohesiveness parameters are shown to be concentrated in the right region, while the remaining analytical parameters are concentrated in the left region.

4. Conclusions

The addition of varying concentrations (0%, 0.5%, 1%, and 1.5%) of sour cherry seed powder to meatballs subjected to various temperatures (150 °C, 200 °C, and 250 °C) exerted a substantial influence on the pH, a*, b*, cooking loss, hardness, springiness, and acrylamide and TBARS contents of the meatballs. The lowest concentrations of TBARS and acrylamide were observed in the samples containing 1% sour cherry seed powder. The sour cherry seed powder increased the total phenolic content and antioxidant capacity of the meatballs; the highest values were generally observed in the meatballs with a 0.5–1% addition and especially at high cooking temperatures, such as 250 °C. The results show that adding phytochemically rich sour cherry seed powder to the meatball formulation reduced acrylamide and lipid oxidation during cooking, preserved and improved the product’s color and texture properties, and increased its antioxidant content; it also enabled sour cherry seeds, a food industry waste product, to be utilized as a value-added component. These phenomena are believed to be attributable to the high antioxidant activity of sour cherry seed powder. In this context, further studies on sour cherry seed powder are recommended.

Specifically, this study is, to our knowledge, the first to demonstrate that sour cherry seed powder, an underutilized agricultural and industrial byproduct, can be effectively incorporated into food formulations to significantly enhance the antioxidant capacity while reducing acrylamide levels. This offers a sustainable and multifunctional solution for both food safety and product development.

Limitations

One of the most significant limitations of the study is the use of only one type of meat (beef) and a single sour cherry variety (Montmorency).