Antioxidative and bioprotective effect of lactic acid bacteria on postharvest strawberry: intact and cell lysates
Résumé
The present study evaluates the antioxidative and the protective effect of the intact and cell lysates of Lactobacillus pentosus on the postharvest strawberry during 10 days of storage at 4 A degrees C. The antioxidant activities of the intact and cells lysates were measured by the inhibition of the lipid perioxidation of beta-carotene/linoleic acid system and the inhibition of the ABTS(.+) oxidation systems. Both techniques showed an increase in the antioxidant capacity for the cell lysates. The effect of the spreading intact cells and cell lysates of L.pentosus on the strawberry's antioxidant capacity and physiochemical properties was compared. The fruit's antioxidant activity was enhanced slightly after adding the intact cells to reach 40 % by the end of the test, whereas that of the cell lysates was about 45 % all along the test. An increase in total phenol content was found for the cell lysates after 3 days of storage, while a gradual raise was noticed for the intact cells. The lyses bacterial cells enhance the fruit color conservation modestly (10 %) but constantly. The bacterial adding preserved the moisture of the postharvest fruit with a water loss reduction of 58.7 and 39.54 %, respectively for intact and cell lysates. Therefore, the molds and yeasts fruit proliferation was inhibited as well especially after 3 postharvest storage days (p < 0.05). Results suggest the presence of intracellular antioxidant bacterial factors that could be helpful not only in the postharvest fruit quality but also as antioxidant food system source to the human body.