The ACC deaminase-producing plant growth-promoting bacteria: Influences of bacterial strains and ACC deaminase activities in plant tolerance to abiotic stress.

Global climate change results in frequent occurrences and/or long durations of abiotic stress. Field grown plants are affected by abiotic stress, and they modulate ethylene in response to abiotic stress exposure and use it as a signaling molecule in stress tolerance mechanisms. However, frequent occurrences and/or long durations of stress conditions can cause plants to induce ethylene levels higher than their thresholds, resulting in a reduction of plant growth and crop productivity. The use of plant growth-promoting bacteria (PGPB) that produce 1-aminocyclopropane-1-carboxylate (ACC) deaminase has increased in various plant species to ameliorate the deleterious effects of stress-induced ethylene and promote plant growth despite abiotic stress conditions. Unfortunately, there are restrictions that limit the use of ACC deaminase-producing PGPB to protect plants from abiotic stresses. This review describes how abiotic stress induces ethylene and how stress-induced ethylene adversely affects plant growth. In addition, this review emphasizes the importance of the compatibility of PGPB strains and specific host plants and ACC deaminase activities in the reduction of stress ethylene and the promotion of plant growth, based on the research published in the last 10 years. Moreover, due to the restrictions in PGPB use, this review highlights the potential generation of transgenic plants expressing the AcdS gene that encodes the ACC deaminase enzyme as a substitute for PGPB in the future to support and uplift agricultural sustainability and food security globally.

Influences of extrusion parameters on physicochemical properties of textured vegetable proteins and its meatless burger patty.

Isolated soy protein, wheat gluten, and starch at ratio 5:4:1 were texturized under different moisture contents (40 and 50%) and die temperature (130 and 150 °C) by the twin-screw extruder. Physicochemical properties were firstly studied. These textured vegetable proteins (TVPs) were used to form 100% plant-based burger patties. Cooking and textural features were secondly investigated. TVP at 50% moisture content and 130 °C die temperature represented the highest water absorption capacity and integrity index but the lowest solubility among TVPs. Cooking loss and shrinkage in diameter and thickness, cohesiveness, chewiness, hardness, and cutting strength of TVP meatless burger patties were significantly lower than that commercial meat patty, while moisture retention and springiness of TVP meatless burger patties were higher (p < 0.05). Our results found that the texture of patty made with TVP at 50% moisture content and 130 °C die temperature was the most similarity to commercial meat patty.

Fermentation of texturized vegetable proteins extruded at different moisture contents: effect on physicochemical, structural, and microbial properties.

To investigate the effect of fermentation on texturized vegetable protein (TVP), TVPs extruded at 40 and 50% feed moisture contents (MC) were fermented using Bacillus subtilis at 37 °C. Physicochemical, structural and microbial properties of TVPs were determined at 0, 12, 24, 36, 48, and 60 h after fermentation. Integrity index of fermented TVPs did not change significantly until 24-36 h after fermentation. Springiness and cohesiveness remained stable after fermentation in all samples. Significant total color change was observed during fermentation. The pH values dropped initially and rose again with a coincident increase in nitrogen solubility index and viable cell count of B. subtilis. During fermentation, TVP extruded at 50% MC maintained higher chewiness, hardness, integrity index, and layered structure than that extruded at 40% MC. The study demonstrated that fermenting the TVP extruded at 50% MC has potential to produce a new type of TVP based B. subtilis fermented food.