A review on fermented vegetables: Microbial community and potential upgrading strategy via inoculated fermentation.

Fermentation is a traditional method utilized for vegetable preservation, with microorganisms playing a crucial role in the process. Nowadays, traditional spontaneous fermentation methods are widely employed, which excessively depend on the microorganisms attached to the surface of raw materials, resulting in great difficulties in ideal control over the fermentation process. To achieve standardized production and improve product quality, it is essential to promote inoculated fermentation. In this way, starter cultures can dominate the fermentation processes successfully. Unfortunately, inoculated fermentation has not been thoroughly studied and applied. Therefore, this paper provides a systematic review of the potential upgrading strategy of vegetable fermentation technology. First, we disclose the microbial community structures and succession rules in some typical spontaneously fermented vegetables to comprehend the microbial fermentation processes well. Then, internal and external factors affecting microorganisms are explored to provide references for the selection of fermented materials and conditions. Besides, we widely summarize the potential starter candidates with various characteristics isolated from spontaneously fermented products. Subsequently, we exhibited the inoculated fermentation strategies with those isolations. To optimize the product quality, not only lactic acid bacteria that lead the fermentation, but also yeasts that contribute to aroma formation should be combined for inoculation. The inoculation order of the starter cultures also affects the microbial fermentation. It is equally important to choose a proper processing method to guarantee the activity and convenience of starter cultures. Only in this way can we achieve the transition from traditional spontaneous fermentation to modern inoculated fermentation.

Modification of pepper seed protein isolate to improve its functional characteristic by high hydrostatic pressure.

Pepper seed protein isolate (PSPI) is a valuable plant-based protein source, yet the impact of processing methods such as high hydrostatic pressure (HHP) on its properties remains unclear. The impact of HHP on the structural and functional properties of PSPI at pH 7 and pH 9 was evaluated. Structural changes in PSPI were analyzed using spectral techniques, revealing significant alterations in the secondary and tertiary structures induced by HHP treatment. HHP treatment caused the unfolding of the PSPI structure, leading to the exposure of previously hidden chromophores and hydrophobic groups. The treatment also led to changes in free sulfhydryl groups and increased average particle size suggesting the formation of macromolecular polymers or insoluble aggregates. Consequently, the water-holding capacity, oil-holding capacity, foaming characteristics, and emulsifying activity index of the modified PSPI were significantly enhanced both at pH 7 and pH 9, with maximum improvements of 121.98 %, 157.29 %, 100.00 %, and 265.78 %, respectively. In conclusion, HHP is a promising strategy for enhancing the physicochemical properties of PSPI for various applications.