Effects of ingredient ratio and packaging on the quality of tofu enriched with wood ear mushroom (Auricularia auricula-judae)

Abstract

This study evaluates the effects of soybean-to-water ratio during grinding, supplementation level of wood ear mushroom (Auricularia auricula-judae), and packaging type on the sensory quality, texture, and storage stability of tofu. In the first experiment, tofu samples were prepared using three soybean-to-water ratios (1:7, 1:8, and 1:9) combined with three levels of mushroom supplementation (1%, 2%, and 3%). Results showed that the 1:8 ratio combined with 2% mushroom yielded tofu with balanced sensory attributes, moderately soft texture, slight crispness contributed by the mushroom, and the highest recovery yield (66.82%). In the second experiment, the optimal tofu formulation was stored for 10 days at 4 ± 2 °C using three types of packaging: polyethylene (PE), polypropylene (PP), and vacuum-sealed polyamide (PA). Sensory characteristics, texture firmness, and total aerobic microbial counts were monitored periodically. Vacuum-sealed PA packaging best maintained product quality, with a slight decrease in firmness (from 75.34 N to 65.37 N) and microbial counts remaining within safe limits. In contrast, samples stored in PE and PP packaging exhibited quality degradation starting from day 6 and exceeded microbiological safety thresholds by the end of the storage period. These results indicate that the combination of a 1:8 soybean-to-water ratio, 2% A. auricula-judae supplementation, and vacuum-sealed PA packaging is an optimal approach to improve the quality and extend the shelf life of tofu enriched with wood ear mushroom.