Hydrolysis of Edible Oils by Fungal Lipases: An Effective Tool to Produce Bioactive Extracts with Antioxidant and Antimicrobial Potential

Hydrolysis of olive, rapeseed, linseed, almond, peanut, grape seed and menhaden oils was performed with commercial lipases of Aspergillus niger, Rhizopus oryzae, Rhizopus niveus, Rhizomucor miehei and Candida rugosa. In chromogenic plate tests, olive, rapeseed, peanut and linseed oils degraded well even after 2 h of incubation, and the R. miehei, A. niger and R. oryzae lipases exhibited the highest overall action against the oils. Gas chromatography analysis of vegetable oils hydrolyzed by R. miehei lipase revealed about 1.1 to 38.4-fold increases in the concentrations of palmitic, stearic, oleic, linoleic and α-linolenic acids after the treatment, depending on the fatty acids and the oil. The major polyunsaturated fatty acids produced by R. miehei lipase treatment from menhaden oil were linoleic, α-linolenic, hexadecanedioic, eicosapentaenoic, docosapentaenoic and docosahexaenoic acids, with yields from 12.02 to 52.85 µg/mL reaction mixture. Folin-Ciocalteu and ferric reducing power assays demonstrated improved antioxidant capacity for most tested oils after the lipase treatment in relation to the concentrations of some fatty acids. Some lipase-treated and untreated samples of oils, at 1.25 mg/mL lipid concentration, inhibited the growth of food-contaminating bacteria. The lipid mixtures obtained can be reliable sources of extractable fatty acids with health benefits.

Combined effect of ultrasound and basic electrolyzed water on the microbiological and oxidative profile of low-sodium mortadellas

Ultrasound (US) and basic electrolyzed water (BEW) are considered emerging technologies; however, few studies have addressed the combination of both technologies in emulsified meat products. This study aimed to evaluate the individual and combined effect of US (25 kHz; 175 W; 20 min) and BEW (pH 10.99; -92.33 mV) on the microbiological and oxidative profile of low-sodium mortadellas (30% of NaCl reduction) stored for 90 days at 5 °C. The use of BEW alone increased the pH and reduced the redox potential of mortadellas, while the US did not affect these parameters. The combined application of US and BEW reduced the lactic acid bacteria counts by up to 0.36 log CFU/g. In addition, BEW stimulated the growth of lipolytic bacteria. The treatments subjected to US application alone showed a lower growth rate of lipolytic bacteria, lower lipid and protein oxidation, and higher ΔE* values. Therefore, the application of US and BEW may be a promising strategy to improve the microbiological and oxidative quality of mortadella during storage.