Abstract: A preparation method for low-temperature sol-agar is provided, including the following steps: Gracilaria after microbial fermentation is subjected to alkaline treatment, cleaning, two steps of acidification and washing, washing, bleaching, gel boiling, dehydration, crushing, screw extrusion, microwave drying, etc., to prepare low-temperature sol-agar. The preparation method for low-temperature sol-agar is adopted in the present invention, an agar product is extracted and modified by a microbial fermentation-assisted alkaline method, and the low-temperature sol-agar is prepared by further combining a thermal denaturation processing technology, which not only improves an application performance of the agar product, but also improves the commercial value of the product, reduces the use of conventional process lye while reducing the production cost, which is green and environmentally friendly.

Abstract: A fermented supernatant of Bangia fusco-purpure and Lactobacillus with an alpha-glucosidase inhibitory activity is provided, where a preparation method for the fermented supernatant of Bangia fusco-purpure and Lactobacillus includes the following steps of: S1: mixing Bangia fusco-purpure with water in a mass/volume ratio of 4.45%-5% to obtain a Bangia fusco-purpure suspension; S2: adding glucose in a mass/volume ratio of 2% to the Bangia fusco-purpure suspension, followed by pasteurization; S3: inoculating Lactobacillus delbrueckii or Lactobacillus plantarum in a mass/volume ratio of 4% to obtain a mixed solution of Bangia fusco-purpure and Lactobacillus; S4: fermenting the mixed solution of Bangia fusco-purpure and Lactobacillus at 37° C.