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Studies on fermentation by acid lactic bacteria (LAB) have confirmed the presence of strains with attributes of considerable relevance for food processing. These strains, in addition to their ability to modify the texture and flavor of foods, possess beneficial properties for human health. They enhance food quality by making it more nutrient-rich and contribute to food preservation. The production of lactic acid, vitamins, exopolysaccharides, and bacteriocins, among other compounds, confers these properties to LAB. In the realm of preservation, bacteriocins play a crucial role. This is because bacteriocins act by inhibiting the growth and reproduction of unwanted microorganisms by interacting with the cell membrane, causing its rupture. This preservative effect has led LAB to have widespread use during food processing. This preservative effect has led to widespread use of LAB during food processing. This review highlights the importance of fermentation carried out by LAB in the food industry and in the bio-preservation of foods. These findings emphasize the relevance of continuing investigations and harness the properties of LAB in food production.

The use of yeasts for the production of proteases has increased in demand in recent years. Y. lipolytica has been reported as a strain with high yields of protease production. This work aimed to evaluate the impact of pH and temperature on the production of proteases using Y. lipolytica in solid-state fermentation (SSF). Soybean, canola meal, cottonseed meal, and sesame meal wastes were used as nutrient sources at seven pH levels (4, 5, 6, 7, 8, 9, 10) and five temperatures (25, 30, 35, 40, 45 °C). The waste source and optimal conditions for maximum enzyme production (EP) were obtained by Box–Benhken design. The results revealed that at pH of 7, temperature of 30 °C, and for 48 h cultivation period, canola meal showed the best EP with 188.75 U/L, followed by soybean with 117.07 U/L, cottonseed meal with 66.71 U/L, and sesame with the lowest production, reaching 88.5 U/L up to 35 °C. The temperature factor exhibited the greatest effect on protease production. The biotechnological and economic potential of canola meal in the production of enzymes is highlighted.

Pomegranate peel is an important source of polyphenols of remarkable interest in the food, pharmaceutical and cosmetic industry. The improved extraction of total polyphenolic compounds (TPC) from pomegranate peel by solid-state fermentation (SSF) was achieved. The Box, Hunter and Hunter (BHH) followed by the central composite design (CCD) processes were performed to assess the effect of the process variables on TPC release. The statistical designs indicate that the best TPC extraction (234.85 mg GAE/gdm) by means of SSF occurs at 42 °C, 50% moisture, 5.0 pH, mineral solution (g/L): NaNO3 (3.83), KH2PO4 (1.52), MgSO4 (4.66) and KCl (1.52) at 36 h. Under the best fermentation conditions TPC (248.78 ± 1.24 mgGAE/gdm) increased 5.96-fold more than values previously reported and antioxidant activity (AA) increased 5.81-fold compared to the value obtained before the SSF optimization. High-value citric acid, α and β punicalin, α and β punicalagin, punigluconin, galloyl-HHDP hexoside and ellagic acid molecules were identified. The increased extraction of TPC by SSF provides a suitable alternative for the valorization of pomegranate peel through the recovery of molecules with high added value with potential use in the food, pharmacy and cosmetic industries; a diversification in the use of food agroindustry by-products is obtained as an approach to the circular economy model through biotechnological processes.

Procyanidins are bioactive molecules with industrial and pharmaceutical relevance, they are present in recalcitrant agro-industrial wastes that are difficult to degrade. In this study, we evaluated the potential consumption of procyanidins from Aspergillus niger and Trichoderma harzianum strains in submerged fermentations. For this purpose, a culture medium containing salts, glucose, and procyanidins was formulated, where procyanidins were added to the medium after the near-total consumption of glucose. The submerged cultures were carried out in amber flasks at 30 °C and 120 rpm. The addition of procyanidins to the culture medium increased the formation of micellar biomass for all the strains used. The use of glucose affected the growth of A. niger GH1 and A. niger HS1, however, in these assays, a total consumption of procyanidins was obtained. These results show that the consumption of procyanidins by fungal strains in submerged fermentations was influenced by the pH, the use of glucose as the first source of carbon, and the delayed addition of procyanidins to the medium. The study showed that A. niger and T. harzianum strains can be used as a natural strategy for the consumption or removal of procyanidins present in recalcitrant residues of risk to the environment and human health.