Hyperbaric Storage Effect on Enzyme Activity and Texture Characteristics of Raw Meat

Abstract

Hyperbaric storage (HS) is a new food preservation alternative or even improvement of cold storage processes. HS of raw pork meat in pieces (PP) and raw bovine minced meat (BM) was compared to conventional refrigeration at 60 MPa/10 °C and 75 MPa/25 °C (conditions at which a previous work reported good potential for shelf life extension), on proteolytic enzymes, texture after cooking, and SEM of raw meat microstructure. Regarding enzymatic activities in PP meat, an overall reduction on the activity of cathepsins B, L, and D and calpains were observed, which were more pronounced for cathepsin B and calpains, with a reduction of 77.5 and 95.3% for PP samples stored at 60 MPa/10 °C and 47.3 and 90.9% for samples stored at 75 MPa/25 °C, respectively, after 60 days of storage. A different scenario was observed for BM samples, where enzymatic activities remained practically unchanged for both HS conditions (except for calpains), when compared to refrigerated storage. Indeed, the reduction of calpain activity in BM at 60 MPa/10 °C was comparable to that of refrigerated storage, while at 75 MPa/25 °C, a significant (p > 0.05) reduction on calpain activity was observed compared either with refrigeration and 60 MPa/10 °C from the 30th day of storage experiments onwards. Additionally, cathepsin L activity decreased along refrigerated storage (approximately 44.4%), while both HS conditions allowed to keep the enzymatic activity unchanged along storage. Regarding texture after cooking, 60 MPa/10 °C revealed to be the preservation condition that better maintained meat textural characteristics during storage. Furthermore, analysis by SEM showed a more pronounced effect of 75 MPa/25 °C on meat microstructure, with muscular fibers showing a smother appearance and a less individualized organization. These results contribute to deepen the knowledge of the effect of HS on raw meat, after previous results have revealed a good possibility of extending the shelf-life of raw bovine and pork meats by HS, either in combination with mild (10 °C) or room-like (25 °C) temperatures.