# Application of High Hydrostatic Pressure (Long Holding Time vs. Two Consecutive Short Cycles) for the Preservation of Lamb Burgers Enriched with Lupinus albus Flour

## TL;DR

This study compares two high-pressure methods for preserving lamb burgers enriched with lupine flour, finding that two short cycles better maintain quality and safety.

## Contribution

The study introduces a novel comparison of HHP treatment durations for preserving lupine-enriched lamb burgers.

## Key findings

- Two short HHP cycles at 600 MPa preserved burger quality better than a single long cycle.
- Lupine flour from compression milling reduced lipid oxidation more effectively.
- HHP significantly reduced microbial counts without affecting sensory scores of grilled burgers.

## Abstract

High hydrostatic pressure (HHP) can extend the shelf life and ensure safety of meat products such as lamb burgers. Lupinus albus variety Orden Dorado (a low alkaloid content variety) flour, rich in protein and phenolic compounds, offers the potential to enhance the preservation of meat products during storage. Lamb burgers were formulated with Lupinus albus flours (1%, w/w; weight/weight), either conventional or obtained by compression milling, and processed by HHP treatments (untreated, two consecutive cycles at 600 MPa for 1 s; or a single cycle at 600 MPa for 4 min), with the total processing time using the HHP unit being the same for both. Then, they were subsequently stored for 14 days under refrigerated conditions. Proximate composition, microbiological changes, color, and oxidation of burgers during storage were evaluated. Flour obtained by compression milling presented higher phenolic compound content, while its antioxidant activity is similar to that obtained by conventional methods. In lamb burgers, the incorporation of both lupine flours maintained the proximate composition and fatty acids profile. Lipid oxidation after 14 days was significantly lower in burgers with lupine flour obtained by compression milling, whereas protein oxidation responses depended on treatment–formulation interactions. HHP drastically reduced microbial counts, with sustained inactivation of coliforms and Escherichia coli (E. coli) although instrumental color was significantly altered in fresh burgers after processing. However, sensory scores of grilled burgers remained unaffected by either flour type or HHP treatment. Incorporation of Lupinus albus flour into lamb burgers processed by HHP preserved sensory quality while enhancing the microbial and lipid oxidation stability of burgers. Finally, the application of two short (1 s) cycles at 600 MPa was more beneficial than a single 4 min cycle, offering similar microbial inactivation with less impact on the quality changes in burgers. Finally, applying two short (1 s) HHP cycles at 600 MPa was more beneficial than a single 4 min cycle, as it achieved similar microbial inactivation while better preserving the color and oxidative stability of the burgers.