Study on the Improvement of Quality Characteristics of Pickles During Fermentation and Storage

Abstract

This study investigated the effect of fermentation-promoting peptides (FPPs) on the improvement of the quality of cowpea pickles during fermentation and storage. FPPs were introduced to evaluate their effects on key parameters such as pH, total acidity, nitrite levels, and salinity. FPP accelerated fermentation by stimulating lactic acid bacteria (LAB) activity, leading to a rapid reduction in pH and a stable increase in total acidity. Nitrite accumulation was peaking at 0.56 mg/kg on the 7th day, compared to 1.37 mg/kg in the control, thus enhancing product safety. FPP also improved antioxidant retention, reducing ascorbic acid degradation by 30% and increasing phenolic retention by 15.97% over the control, which is essential for antioxidant capacity and color stability. Texture analysis showed higher hardness preservation in the presence of FPP, in which hardness decreased from 209.70 g to 79.98 g in the FPP group after storage, compared to a decline from 158.56 g to 41.66 g in the control. Additionally, sensory evaluations demonstrated that the FPP group maintained superior flavor, texture, and appearance, with minimized browning due to improved pectin stability. This research presents FPPs as a promising additive for producing high-quality, shelf-stable pickles in line with clean label trends.

Keywords: anti-browning and texture retention; cowpea pickle quality; fermentation-promoting peptides.

Figure 1

Changes in lactic acid bacteria (a), total bacterial (b), pH (c), total acid content (d), nitrite (e), and salinity (f) of cowpea pickles during fermentation. a, b: significant differences between different groups under the same treatment; *: significant differences under different treatments within the same group (p < 0.05); ns: not significant.

Figure 2

Effects of different treatments on L* value (a), a* value (b), b* value (c) and BI value (d) of cowpea pickles during fermentation and storage. *: significant differences under different treatments within the same group (p < 0.05); **: significant differences under different treatments within the same group (p < 0.01); ns: not significant; a–c: significant differences between different groups under the same treatment.

Figure 3

Texture changes, hardness (a), fracturability (b), chewiness (c) and pectin content (d) of cowpea pickles during fermentation and storage with different treatments. *: significant differences under different treatments within the same group (p < 0.05); **: significant differences under different treatments within the same group (p < 0.01); ns: not significant; a–c: significant differences between different groups under the same treatment.

Figure 4

Sensory evaluation results, color (a), flavor (b), texture (c) and taste (d) of cowpea pickles with different treatments during fermentation and storage. *: p < 0.05; **: p < 0.01; ***: p < 0.001; ****: p < 0.0001.