Changes in the activities of antimicrobial, antitumor, and antioxidant properties of postbiotics (YCG) are related to changes in the composition of phenolic compounds. Antimicrobial activity was found to be highest in postbiotic (YCG-7) against P. aeruginosa, S. aureus, and E. faecalis with an MIC of 3.1 µg/mL. YCG-7 revealed the most cytotoxicity against LS-174T and PC-3 cell lines with an IC₅₀ of 5.78 and 6.56 µg/mL, respectively. YCG-7 was far more effective for scavenging free radicals in the NO^• and DPPH assays with a scavenging activity of 70.73% and 85.6%, respectively. YCG-7’s total phenolic acid content is up to eightfold higher compared with control. Escherichia coli Nissle 1917 retained high viable counts during refrigerated storage, particularly in YCG (>10⁸ cells g⁻¹) revealing a potential prebiotic activity of Cape gooseberry juice. EcN affected the phenolic profile of the YCG. Pyrogallol, p-coumaric acid, ellagic acid, 4-hydroxybenzoic acid, salicylic acid, gallic acid, vanillic acid, o-coumaric acid, caffeic acid, catechol, syringic acid, and rutin were the predominant phenolic compounds in YCG-7 or YCG-15. Chlorogenic, rosmarinic, cinnamic acid, naringin, and kaempferol were degraded by EcN in YCG-7 and YCG-15. The YCG had significantly higher sensory scores for appearance, smoothness, sourness, mouthfeel, and overall acceptance. These results provide the basis to target the functional benefits of YCG for further human health applications.

The aim of this study was to evaluate fig (Ficus carica L.) leaves’ extract (FLE), olive (Olea europaea L.) leaves’ extract (OLE), and their mixture (MLE), to extend the shelf life of pasteurized milk. OLE, FLE, and their mixture MLE (1:1) were added to the pasteurized milk in different concentrations (0.2%, 0.4%, and 0.6%). Several tests were then conducted to determine the activity of these extracts. The antioxidant activity as IC₅₀ was determined by using DPPH radical assay. FLE showed higher IC₅₀ (30.21 µg/mL) compared to the IC₅₀ of OLE (22.43 µg/mL). Phenolic compounds were identified by using high-performance liquid chromatography (HPLC). The highest antimicrobial activity was obtained with 0.6% concentration. Organoleptic properties indicated that the addition of these extracts did not affect the sensory properties of pasteurized milk. Pasteurized milk treated with 0.6% of FLE, OLE, and MLE has significantly decreased (p ≤ 0.05) lipase and protease activity during the storage period, at 5 °C. The results indicated that extending the shelf life of pasteurized milk from 5 to 16 days was successfully achieved through using 0.6% of FLE, OLE, and MLE. The combination of the two extracts (MLE) provides an efficient and safe method to prolong the shelf life of pasteurized milk, without altering the properties of pasteurized buffalo milk.

The AgNPs were synthesized using water‐soluble polysaccharides extracted from the Leucaena leucocephala seeds. The UV‐visible spectrum of the AgNPs showed a sharp absorption peak at 448 nm. The XRD analysis showed four major peaks of the crystalline AgNPs with planes of a face‐centered cubic lattice of silver. The EDS spectrum showed a strong signal peak at ~3 keV. TEM and SEM observations showed the spherical shape of AgNPs with no particle agglomeration, and the size ranged from 8 to 20 nm. AgNPs were highly stable at ‐14.2 mV by zeta potential measurement. AgNPs showed significant anticancer activity against the cell lines of breast cancer, liver carcinoma, and colon carcinoma with the IC₅₀ value of 22.5, 12.3, and 8.9 μg mL^-1, respectively. AgNPs at 900 μg mL^-1 exhibited considerable antifungal activity against ten fungal pathogens. Water‐soluble polysaccharide has the ability to synthesize AgNPs keeping strong antitumor, antifungal activities. The AgNPs can slow down spoilage of composite milk samples at different temperatures. In addition, the accuracy of milk‐IR‐analyses was not affected by different concentrations of AgNPs.

Multi-stress resistance is a widely documented and fascinating phenotype of lactococci where single mutations, preferentially in genes involved in nucleotide metabolism and phosphate uptake, result in elevated tolerance to multiple stresses simultaneously. In this report, we have analysed the metabolic basis behind this multi-stress-resistance phenotype in Lactococcus lactis subsp. cremoris MG1363 using acid stress as a model of multi-stress resistance. Surprisingly, we found that L. lactis MG1363 is fully resistant to pH 3.0 in the chemically defined SA medium, contrary to its sensitivity in the rich and complex M17 medium. When salvage of purines and subsequent conversion to GTP was permitted in various genetic backgrounds of L. lactis MG1363, the cells became sensitive to acid stress, indicating that an excess of guanine nucleotides induces stress sensitivity. The addition of phosphate to the acid-stress medium increased the stress sensitivity of L. lactis MG1363. It is also shown that high intracellular guanine nucleotide pools confer increased sensitivity to high temperatures, thus showing that it is indeed a multi-stress phenotype. Our analysis suggests that an increased level of guanine nucleotides is formed as a result of an improved conversion of guanosine in the salvage pathway. Based upon our findings, we suggest that L. lactis MG1363 is naturally multi-stress resistant in habitats devoid of any purine source. However, any exogenous purine that results in increased guanine nucleotide pools renders the bacterium sensitive to environmental stresses.

The aqueous extract of Moringa oleifera contained a bioactive compounds namely tannins, flavonoids, saponin, alkaloids and terpens. The aqueous extract has high content of total phenolic (340.82 mg/g as gallic acid), In addition to IC 50 of Moringa oleifera extract was 75.82 µg/ml, and therefore the addition of Moringa oleifera extract to yogurt enhances the nutritional value of the resultant yogurt. The aqueous extract exhibited a antibacterial activity against Gram positive bacteria (S. aureus , E. faecalis and B. cereus), in contrast to Gram negative (E.coli and S. Typhimurium) more resistance to extract of Moringa oleifera. The total solid of yogurt is directly proportional to addition of extract content. A slightly decrease in pH was noticed in yogurt enriched aqueous extract. The use of Moringa oleifera extract at mentioned concentration rates increased significantly curd tension and WHC, in addition to susceptibility of synersis was decrease. The addition of aqueous extract of Moringa oleifera enhanced sensory properties of the resultant yogurt. Acetaldehyde and diacetyl increased in yogurt with Moringa oleifera extract, compare with control. Hardness, Adhesiveness and gumminess were significantly higher (P> 0.05) in experimental yogurt made by using different concentration of aqueous extract of Moringa oleifera than control. However, the cohesiveness and springiness were significantly lower in samples of experimental yogurt made with different concentration of aqueous extract of Moringa oleifera than control.