The Effect of Lactiplantibacillus plantarum x3-2b Bacterial Powder on the Physicochemical Quality and Biogenic Amines of Fermented Lamb Jerky

In this study, a protective agent was added to prepare a high-activity Lactiplantibacillus plantarum x3-2b bacterial powder as a fermentation agent and explore its effect on the physicochemical quality, biogenic amines, and flavor of fermented lamb jerky. A composite protective agent, composed of 15% skim milk powder and 10% trehalose, was used, and bacterial mud was mixed with the protective agent at a 1:1.2 mass ratio. The resulting freeze-dried bacterial powder achieved a viable count of 5.1 lg CFU/g with a lyophilization survival rate of 87.58%. Scanning electron microscopy revealed enhanced cell coverage by the composite protective agent, maintaining the cell membrane's integrity. Inoculation with x3-2b bacterial powder increased the pH and the reduction in aw, enhanced the appearance and texture of fermented lamb jerky, increased the variety and quantity of flavor compounds, and reduced the accumulation of biogenic amines (phenethylamine, histamine, and putrescine). This research provides a theoretical basis for improving and regulating the quality of lamb jerky and establishes a foundation for the development of bacterial powder for the commercial fermentation of meat products.

Towards Sustainable Green Adjuvants for Microbial Pesticides: Recent Progress, Upcoming Challenges, and Future Perspectives

Microbial pesticides can be significantly improved by adjuvants. At present, microbial pesticide formulations are mainly wettable powders and suspension concentrations, which are usually produced with adjuvants such as surfactants, carriers, protective agents, and nutritional adjuvants. Surfactants can improve the tension between liquid pesticides and crop surfaces, resulting in stronger permeability and wettability of the formulations. Carriers are inert components of loaded or diluted pesticides, which can control the release of active components at appropriate times. Protective agents are able to help microorganisms to resist in adverse environments. Nutritional adjuvants are used to provide nutrients for microorganisms in microbial pesticides. Most of the adjuvants used in microbial pesticides still refer to those of chemical pesticides. However, some adjuvants may have harmful effects on non-target organisms and ecological environments. Herein, in order to promote research and improvement of microbial pesticides, the types of microbial pesticide formulations were briefly reviewed, and research progress of adjuvants and their applications in microbial pesticides were highlighted, the challenges and the future perspectives towards sustainable green adjuvants of microbial pesticides were also discussed in this review.

Nanocurcumin, Promising Potential Protective Agent Against Histopathological Damage in the Cerebral Cortex of Mice Induced by Aluminum Chloride

<b>Background and Objective:</b> Aluminum (Al) is widely used in many aspects of daily life, such as food packaging, cooking utensil components, food additives, cosmetics and water distillation. This study aimed to evaluate the protective role of nanocurcumin on the cerebral cortex of one and two-month-old mice exposed to 200 mg kg<sup></sup><sup>1</sup> b.wt., aluminium. <b>Materials and Methods:</b> The Swiss Webster mice were used in this study. The control group only received sterile distilled water, the Al group was administered 200 mg kg<sup></sup><sup>1</sup> b.wt., of AlCl<sub>3</sub> solution and the Al+Na Cur group was administered 200 mg kg<sup></sup><sup>1</sup> b.wt., AlCl<sub>3</sub>+200 mg kg<sup></sup><sup>1</sup> nanocurcumin by intraperitoneal injection. The nanocurcumin was administered one hour after AlCl<sub>3 </sub>exposure and then on days 0, 3, 6, 9, 12, 15, 18, 21, 24, 27 and 30. All the mice were anaesthetized and their brains were collected and fixed in a neutral formalin buffer solution for histological analysis. The paraffin method was used in this study. <b>Results:</b> The death of granular neuron cells and karyolysis cells and the vacuolation of the pyramid cell layer of the cerebral cortex could be prevented by the intraperitoneal administration of nanocurcumin. The effect of nanocurcumin administration on the Al group at two months of age was more effective than on the Al group at one month of age. <b>Conclusion:</b> Nanocurcumin can be a promising candidate protective agent against cerebral cortex changes after aluminium administration.

Hydroxypropyl β-cyclodextrin improving multiple stresses tolerance of Lactococcus lactis subsp. lactis

L. lactis is known as industrial starter in the fermentation of dairy and meat products, and it plays an important role in human health as an edible probiotic. During industrial production, L. lactis often experiences different stresses that delay the growth and decrease the survival in some serious conditions. In this study, the protective effects of hydroxypropyl β-cyclodextrin (HP β-CD) on L. lactis under multiple stresses were investigated. The microbial cells were treated with different stresses including heat, NaCl, cold, and H₂ O₂ stresses, and the results were showed by measuring the OD₆₀₀ or spot plating method. The growth and tolerance were improved when HP β-CD was added during different stress conditions, better than that of trehalose. Besides, the scanning electron microscopic and fluorescence spectrum studies showed that HP β-CD could combine with L. lactis to protect the cell structure, suggesting that HP β-CD may act as a protective agent of L. lactis. Therefore, HP β-CD could be considered as a potential protective agent to be applied in food industry, and its protective mechanism on L. lactis still needs further investigation.

Whey Protein Concentrate, Pullulan, and Trehalose as Thermal Protective Agents for Increasing Viability of Lactobacillus plantarum Starter by Spray Drying

It is necessary to add protective agents for protecting the probiotic viability in the preparation process of probiotics starter. In this study, we used whey protein concentrate (WPC), pullulan, trehalose, and sodium glutamate as the protective agent and optimized the proportion of protective agent and spray-drying parameters to achieve the best protective effect on Lactobacillus plantarum. Moreover, the viable counts of L. plantarum in starter stored at different temperatures (-20°C, 4°C, and 25°C) for 360 days were determined. According to response surface method (RSM), the optimal proportion of protective agent was 24.6 g/L WPC, 18.8 g/L pullulan, 16.7 g/L trehalose and 39.3 g/L sodium glutamate. The optimum spray-drying parameters were the ratio of bacteria to protective agents 3:1 (v: v), the feed flow rate 240 mL/h, and the inlet air temperature 115°C through orthogonal test. Based on the above results, the viable counts of L. plantarum was 12.22±0.27 Log CFU/g and the survival rate arrived at 85.12%. The viable counts of L. plantarum stored at -20°C was more than 1010 CFU/g after 200 days.

Silver Nanoparticles Based Ink with Moderate Sintering in Flexible and Printed Electronics

Printed electronics on flexible substrates has attracted tremendous research interest research thanks its low cost, large area production capability and environmentally friendly advantages. Optimal characteristics of silver nanoparticles (Ag NPs) based inks are crucial for ink rheology, printing, post-print treatment, and performance of the printed electronics devices. In this review, the methods and mechanisms for obtaining Ag NPs based inks that are highly conductive under moderate sintering conditions are summarized. These characteristics are particularly important when printed on temperature sensitive substrates that cannot withstand sintering of high temperature. Strategies to tailor the protective agents capping on the surface of Ag NPs, in order to optimize the sizes and shapes of Ag NPs as well as to modify the substrate surface, are presented. Different (emerging) sintering technologies are also discussed, including photonic sintering, electrical sintering, plasma sintering, microwave sintering, etc. Finally, applications of the Ag NPs based ink in transparent conductive film (TCF), thin film transistor (TFT), biosensor, radio frequency identification (RFID) antenna, stretchable electronics and their perspectives on flexible and printed electronics are presented.

Enhancement of viability, acid, and bile tolerance and accelerated stability in lyophilized Weissella cibaria JW15 with protective agents

Dietary supplementation with lactic acid bacteria to maintain or improve intestinal health is advocated. Weissella spp. are present in different fermented vegetable-based foods like kimchi, as well as in the normal gastrointestinal (GI) tract of humans. Weissella cibaria strains have been proposed as potential probiotics. Freeze-drying is a promising treatment method for these strains for industrial applications and to increase the accessibility of their health-promoting benefits. Moreover, probiotic strains need to be able to survive in the host GI tract, and acid and bile are both environmental stressors that can reduce strain survival. Therefore, this study evaluated the effect of the combination of protective agents on the acid and bile resistance of W. cibaria JW15 after freeze-drying. A protective agent combination with a 1:1 ratio of 5 g + 5 g/100 ml w/v soy flour + yeast extract (SFY) retained nearly 100% viability after freeze-drying and was resistant to artificial bile acids. Remarkably, skim milk + soy flour (SSF) was resistant to an acidic solution, and the viability of W. cibaria JW15 in artificial gastric acid was enhanced when treated with this mixture. Furthermore, SFY and SSF were found to maintain high numbers of viable cells with a low specific rate of cell death (k) after storage at 50°C, 60°C, and 70°C. These results support an effective probiotic formulation system with a high number of viable cells, and its protective effects can be leveraged in the development of probiotic products with health benefits.

Production of freeze-dried yeast culture for the brewing of traditional sorghum beer, tchapalo

Freeze‐drying is a well‐known dehydration method widely used to preserve microorganisms. In order to produce freeze‐dried yeast starter culture for the brewing purpose of African sorghum beer, we tested protective agents (sucrose, glucose, glycerol) in combination with support materials (millet, maize, sorghum, and cassava flours) at 1:1 ratio (v/v). The yeast strains Saccharomyces cerevisiae F_12–7 and Candida tropicalis C_0–7 previously isolated from sorghum beer were used in a mixed culture at a ratio of 2:1 (C. tropicalis/S. cerevisiae). After the freeze‐drying, the residual water contents were between 0.78 –2.27%, 0.55 –4.09%, and 0.40–2.61%, respectively, with sucrose, glucose and glycerol. The dried yeasts viabilities were between 4.0% and 10.6%. Among the protective agents used, sucrose was found to be the best protectant giving cell viabilities of 8.4–10.6%. Considering the support materials, millet flour was the best support after drying. When the freeze‐dried yeast powders were stored at 4°C and room temperature (25–28°C) for up to 3 months, the survival rates were the highest with cassava flour as the support material.