Effects of Different Fermentation Strains on the Antioxidant Activities and Flavor Substances of Morinda citrifolia L. (Noni) Fruit Jiaosu

In order to compare the effects of fermentation by different strains on the quality of noni fruit Jiaosu, noni juice was fermented with Lactobacillus rhamnosus 12 (LGG), Lactobacillus plantarum 08 (LP-08), Lactobacillus plantarum K11 (LP-K11), Pediococcus pentosaceus 03 (PP) and Bifidobacterium lactis 36 (BLA), respectively. The effects of different strains on the physicochemical properties, antioxidant activities and flavor substances of noni juice were investigated. The results showed that among the five strains, LP-08 had the strongest organic acid-producing ability at the end of fermentation, followed by BLA. LP-08 also had the strongest ability to utilize reducing sugar. After 5 days of fermentation, the polyphenol contents were significantly increased by 29.74% and 28.54% from the original level (P<0.05) after fermented with LP-08 and LP-K11, respectively. The activity of SOD was increased by 44.59% on the third day of BLA fermentation and by 43.58% on the fifth day of LP-08 fermentation (P<0.05). The antioxidant activities of noni fruit Jiaosu were enhanced by fermenting with LP-08, LP-K11 and BLA for 3~7 days. The lactic acid content was significantly increased by 23.89 times after fermented with BLA, followed by LP-K11 and LP-08. The best overall sensory quality was obtained after fermented with LP-08, 10 kinds of small molecular organic acids, 5 kinds of alcohols and their derivatives, 4 kinds of aldehydes and 3 kinds of esters were created during fermentation, which endows noni fruit Jiaosu with cheese, floral aromas and fruity. Compared with other strains, LP-08 demonstrated stronger ability to produce acid and SOD, it also contributed to the superior antioxidant properties and sensory qualities of noni fruit Jiaosu. Therefore, LP-08 had great research and application potential in the production of noni fruit Jiaosu.