Microscopic Image Segmentation and Morphological Characterization of Novel Chitosan/Silica Nanoparticle/Nisin Films Using Antimicrobial Technique for Blueberry Preservation

In the current work, the characterization of novel chitosan/silica nanoparticle/nisin films with the addition of nisin as an antimicrobial technique for blueberry preservation during storage is investigated. Chitosan/Silica Nanoparticle/N (CH-SN-N) films presented a stable suspension as the surface loads (45.9 mV) and the distribution was considered broad (0.62). The result shows that the pH value was increased gradually with the addition of nisin to 4.12, while the turbidity was the highest at 0.39. The content of the insoluble matter and contact angle were the highest for the Chitosan/Silica Nanoparticle (CH-SN) film at 5.68%. The use of nano-materials in chitosan films decreased the material ductility, reduced the tensile strength and elongation-at-break of the membrane. The coated blueberries with Chitosan/Silica Nanoparticle/N films reported the lowest microbial contamination counts at 2.82 log CFU/g followed by Chitosan/Silica Nanoparticle at 3.73 and 3.58 log CFU/g for the aerobic bacteria, molds, and yeasts population, respectively. It was observed that (CH) film extracted 94 regions with an average size of 449.10, at the same time (CH-SN) film extracted 169 regions with an average size of 130.53. The (CH-SN-N) film presented the best result at 5.19%. It could be observed that the size of the total region of the fruit for the (CH) case was the smallest (1663 pixels), which implied that the fruit lost moisture content. As a conclusion, (CH-SN-N) film is recommended for blueberry preservation to prolong the shelf-life during storage

Conformational and Functional Properties of Soybean Proteins Produced by Extrusion-Hydrolysis Approach

The conformational and functional changes of soybean protein after a hybrid extrusion-hydrolysis method were evaluated. Three extrusion temperatures (60, 80, and 100°C) were used prior to enzymatic hydrolysis. The hydrolysis degrees, molecular weight profiles, solubilities, surface hydrophobicities, sulphydryl contents, disulfide bound, water holding capacity, emulsion, and foam properties of the protein isolated from the enzyme-hydrolyzed extruded soybeans were analyzed. It shows that extrusion caused significant changes in the hydrophobicity, molecular weight distribution, solubility, surface hydrophobicity, emulsification activity, and stability of the protein. The increase of molecular weights could be attributed to the formation of protein aggregates during extrusion. Extrusion and enzymatic hydrolysis led to a sharp increase in the number of disulfide bonds with a decrease of the sulphydryl group. The water holding capacity and the solubility of protein increased with the increase of extrusion temperature and hydrolysis time. Extrusion improved the emulsifying activity but reduced the emulsifying stability of the recovered proteins. Extrusion improved the foam capacity but reduced the foam stability of the proteins. The data demonstrated that the extrusion-hydrolysis treatment significantly altered the conformational and functional properties of soybean protein, which may be further optimized for the development of new soy protein ingredient with desired functional properties

Effect of Titanium Dioxide Nanocomposite Material and Antimicrobial Agents on Mushrooms Shelf-Life Preservation

Mushrooms have limited shelf-life and it can be prolonged if suitable conditions and treatments are effectively applied. In this study, nanocomposite material and antimicrobial agents with a combination of chitosan were used as novel packaging material for mushroom preservation. The microbiological analysis, physicochemical properties, headspace gas analysis, and polyphenol oxidase activity (PPO) during cold storage were investigated. As compared with control, coated mushrooms with chitosan (CHS), and nano-titanium dioxide CHSTiO2 thymol + tween-80 CHSTiO2/TT80 coating treatment showed significantly (p ≤ 0.05) lower respiration rate, microbial contaminations (4.27 log CFU/g), and (5.93 log CFU/g) for total yeast/mold and aerobic plate counts, respectively. The weight loss ratio was the lowest for CHSTiO2/TT80 (10.88% loss) followed by CHSTiO2 (11.76% loss). CHSTiO2/TT80 recorded a higher electrolyte leakage rate (25.84%) and acidity. While the lowest PPO activity was established for CHSTiO2 (17.09 U mg−1 Protein), while the lowest values for total soluble solid concentrations were reported for CHSTiO2/TT80 mushrooms (4.91%). These results indicated that CHSTiO2/TT80 coating treatment might delay the aging degree of white button mushrooms and be investigated as a novel packaging material for other food products in the future

Investigating the Nano-Films Effect on Physical, Mechanical Properties, Chemical Changes, and Microbial Load Contamination of White Button Mushrooms during Storage

Nutrient-rich edible white button mushrooms were coated with Chitosan (1%), Chitosan/nano-silica, and Chitosan/nano-titanium and then stored at 4 °C to investigate the physical, mechanical properties, chemical changes, and microbial load contamination at an interval of 3 days up to a 12 days storage period. It was noticed that Chitosan/nano-titanium and Chitosan/nano-silica preserved the weight loss percentages as 11.80% and 12.69%, respectively. Treatment with Chitosan/nano-silica coating was found to have positive impacts on the overall color parameters. Both of the nano-coating films enhanced headspace gas compositions and firmness. Chitosan/nano-silica samples recorded the least electrolyte leakage value (24.44%), as low oxygen gas concentration can reduce the respiration rate, weight loss, and cap opening. Chitosan/nano-titanium treatment showed the lowest cap opening value (19.58%), PPO activity (16.98 mg−1 protein), and microbial load contamination (6.12 log CFU/g) at the end of the whole storage period, suggesting that nano-films are a promising preservation method for prolonging the white button mushroom’s shelf-life

The Response of Globe Artichoke Plants to Potassium Fertilization Combined with the Foliar Spraying of Seaweed Extract

This work investigated the effects of potassium mineral fertilizers, combined with biofertilizers (T1–T4 treatments) and the foliar spraying of seaweed extract (at 1 g/L, 2 g/L, and 3 g/L) on the vegetative growth characters, chemical constituents of foliage, and the yield and quality parameters of globe artichoke. The maximum height, and the fresh and dry weight of the leaves, was recorded in plants that received only soil with added potassium (T1 treatment) and sprayed with seaweed extract at 3 g/L. Furthermore, the highest number of offshoots per plant was registered in the T2 treatment combined with seaweed extract (3 g/L). T1 and T2 treatments resulted in the highest values of leaf N, P, K, and total carbohydrate content when combined with seaweed extract (3 g/L). The highest numbers of early, late, and total heads per plant were obtained for the T1 treatment and seaweed extract (3 g/L). Similarly, most of the head quality parameters were beneficially affected by the T2 treatment and seaweed extract (3 g/L). In conclusion, it is suggested that soil application of mineral potassium fertilizer (75% of RD) combined with biofertilizer (25% of RD) and the foliar spraying of seaweed extracts at 3 g/L, was most beneficial for the yield and quality parameters of globe artichoke plants