Immobilization of enzymes into nanofiber membranes via electrospinning and its application in natural sweetener production

Abstract

Non-caloric artificial sweeteners (NAS) are currently the world's most widely used food additives, which are considered safe and contributed to good health. But recent research shows that there are still controversies. Therefore, natural sweeteners had gained much attention as NAS substitutes. Recently, the fastest growing market of natural sweetener is the sweeteners made from monk fruit, because its extracts are highest in sweetness among various natural sweeteners and parts of the sweetness compounds have significant anti-diabetic activity. However, one of the components in monk fruit extracts called Siamenoside I (S I), which found to be the most sweetness compound and taste most closely to sucrose, are relatively low in contents. In addition, the Mogroside III E (MG III E), which is lower in sweetness compared to S I but with significant anti-diabetic properties, are also low in contents in the natural monk fruit extracts. As the results, the developing of methods to enrich the contents of S I and MG III E in monk fruit extracts and related products are the goals for the current natural sweetener manufacturers. The bitter tastes and flavors of saponins containing functional foods and related beverages are still the issues to be addressed. For example, the modification of glycoside linkage patterns of saponins including oleuropeins, ginsenosides, and momordicosides could achieve the debittering purpose and meet the consumers' preferences. Therefore, the goals of this research are to immobilize specific enzymes using electrospinning. Together with the high throughput microreactor, and the continuous packed-bed column, we suppose that we could obtain a fair amount of S I and MG III E through enzyme transformation of MG V and improve the taste of monk fruit extracts as natural sweeteners. Support or Funding Information This research was supported by the by the National Science Council of Taiwan (NSC Grant 106-2218-E-029-002-MY2). The screening of yeast transformants having its exg1Δ::kanMX4 replaced by DbExg1-His-URA3 cassette which has S I bioconversion activity A. Ura− and G418 resistance selection. B. The genotype confirmation of yeast transformants. Successful transformants have 3523 b.p product. Numbers represent candidates relative to candidates in A. C. Screening of transformants with siamenoside I production specificity. Peak 1, mogroside V; 2, siamenoside I; 3, mogroside IV; 4, mogroside IIIE. SEM images and size distribution of electrospun nanofibrous membrane: (Upper panel) PVA; (Lower panel) cross-lined PVA. SEM images and size distribution of electrospun nanofibrous membrane: (Upper panel) PVA with 0.5% of the enzyme; (Lower panel) cross-lined PVA with 0.5% of the enzyme. SEM images and size distribution of electrospun nanofibrous membrane: (Upper panel) PVA with 2.0 % of the enzyme; (Lower panel) cross-lined PVA with 2.0% of the enzyme. This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.