Extraction of phenolic compounds and flavonoids from tomato residues using high-pressure-temperature advanced method

TL;DR

This study explores a new high-pressure-temperature method to extract valuable compounds from tomato waste, showing it to be more efficient than traditional techniques.

Contribution

The first use of a high-pressure-temperature reactor for extracting phenolic and flavonoid compounds from tomato residues is introduced and validated.

Findings

Maximum extraction yields of 31.2% for stems and 53.9% for leaves were achieved under moderate conditions.

Optimal extracts showed strong antioxidant activity and significant anti-elastase potential.

Parr reactor extraction outperformed conventional and emerging techniques in yield, selectivity, and efficiency.

Abstract

Tomato residues in the Agadir region constitute a large and under-exploited source of biomass, rich in bioactive molecules such as phenolic and flavonoid compounds. This study highlights, for the first time, the use of high-pressure-temperature reactor as an innovative and advanced extraction technology to recover phenolic acids and flavonoids from stems and leaves of tomato waste. A multivariate optimization approach was designed to assess the effect of temperature, pressure, extraction time, and solvent ratio on the extraction efficiency to determine the optimal conditions. The performance of this method was compared to conventional and emerging techniques (Soxhlet, maceration, and ultrasound-assisted extraction), while the biological activities of the extracts were evaluated via their antioxidant and enzymatic properties. The results showed a maximum extraction yield of 31.2% for stems and 53.9% for leaves under moderate conditions (25 °C, 180 min, 10 bar, 30% ethanol). The highest levels of phenolic compounds (1240.89 mg GA/g extract) and flavonoids (59.32 mg QE/g extract) were obtained at 160 °C and 10 bars, with ethanol concentrations between 70% and 100%. Pareto analysis identified temperature and solvent polarity as the key variables influencing extraction efficiency. The optimal extracts demonstrated strong antioxidant activity (up to 85% DPPH inhibition and 261.8 mg trolox/g extract in the FRAP test) as well as significant anti-elastase potential (>90% inhibition), highlighting their potential for cosmetic and nutraceutical applications. Compared to conventional and advanced techniques already available on the market, Parr reactor extraction offers superior yield, selectivity, and process efficiency. This study validates its role as an environmentally friendly and scalable alternative for the recovery of tomato processing waste within a circular bioeconomy.

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