Protein content claims and nutritional quality of high‑moisture meat analogues (HMMAs)

Addressing global challenges in environmental sustainability and food security among a growing population demands exploring alternative protein sources for human consumption. Industry by-products as ingredients for novel food products can promisingly enhance food system sustainability. This study investigated the nutritional quality and protein content claims of high-moisture meat analogues (HMMAs) produced through extrusion, with blends of soybean protein isolate and sunflower seed meal (after expeller oil extraction), with the feed moisture content of 70% (wet basis). This work evaluated the impact of different sunflower seed meal (SFM) concentrations (37.5%-62.5% of the total weight) on nutritional attributes, such as protein content, amino acid composition, and in vitro protein digestibility. These aspects aligned with FAO/WHO guidelines demonstrated how reference amino acid requirements influence HMMAs’ protein quality and content claims. The in vitro–protein digestibility corrected amino acid score (IV–PDCAAS) and in vitro–digestible indispensable amino acid score (IV–DIAAS) showed variations in HMMAs’ protein quality based on different amino acid scoring patterns. The IVPD, IV–PDCAAS, IV–DIAAS were up to 90.8%. Particularly, HMMAs from a 37.5% SFM blend exhibit no indispensable amino acid deficiency, while SFM 50% and 62.5% presented lysine as the first-limiting amino acid. It highlights the potential of SFM and soybean protein blends for creating nutritious meat alternatives. Using the PDCAAS interpretation, SFM 37.5 and 50% samples qualified for an “excellent source of protein” claim. However, for DIAAS interpretation, all IV–DIAAS samples had a “good source of protein” claim due to the threshold of 100% for “excellent” protein claims, emphasizing the need to reevaluate criteria for making protein content claims on food proteins. Overall, this research provides valuable insights into the impact of replacing soybean protein with SFM on HMMAs’ nutritional quality, contributing to value addition to this underutilized food industry by-product.