Monitoring the spoilage of plant-based meat alternatives during cold storage: Chemical and microbial degradations

Plant-based meat alternatives are receiving increasing attention globally as a sustainable and ethical substitutes for animal meats, while mimicking the flavor attributes and retaining the nutritional quality. Most recent studies focused on the product formulation and optimization on the eating quality of meat analogues, while research on the quality decrease and spoilage mechanisms of these products are underexplored. The present study comprehensively evaluated the deterioration of two commercial products, plant-based ground meat made from pea protein and meat patty made from soy protein, over 7 days at refrigerated storage. Both samples were subject to significant color change, especially in the lightness caused by the surface glossiness. Based on 16S rRNA gene sequencing, it was found that the main spoilage bacteria in the ground and patty samples were Carnobacteria and Rothia , respectively. The degree of microbial spoilage in the patty samples was lower, suggesting a higher stability. During prolonged refrigerated storage, both samples exhibited higher level of volatile basic nitrogen compounds and less free amino acids, revealing substantial protein degradation. The spoilage of plant-based ground meat also showed significant pH decline and acidity increase, which was well correlated with the growth of lactic acid bacteria. Overall, this study provides the foundation for further developing advanced preservation and processing techniques for plant-based meat alternatives in the food industry.