Does the Plant Matrix Type Have Impact on Rutin Transformation During Its Extraction?

Stability of stevioside in food processing conditions: unexpected recombination of stevioside hydrolysis products in ESI source

Stevioside is the main and the sweetest glycoside of stevia plant. It is attractive as a natural sweetener to diabetics and others on carbohydrate-controlled diets. This paper discusses the stability of stevioside under food processing conditions. It was found that stevioside was transformed not only to rubusoside, steviolbioside, steviol monoside and steviol but also to previously unknown stevioside α-anomer and rubusoside α-anomer. Those two identified stevioside transformation products are formed not only during the heating of acidic, neutral and alkaline stevioside standard solutions and stevia leaves suspensions in water and ethanol/water solvents but also during the processing of foods containing stevia. Apart from presenting the new compounds, the paper additionally shows that the recombination of sugar moiety with steviolbioside molecule in MS/ESI source can occur. The effect of molecule recombination in the MS source is known from the literature; however, it has not been reported previously in relation to stevioside derivatives.

Characterization of sustained-release chitosan film loaded with rutin-β-cyclodextrin complex and glucoamylase

ABSTRACT

Edible chitosan film incorporated with rutin-β-cyclodextrin was developed and characterized. The delivery of rutin was improved via the hydrolyzation function of glucoamylase, and the antioxidant activity of the chitosan film was enhanced by the addition of rutin. Sodium bicarbonate solution at different pHs (pH-adjusting reagent) was employed to afford the mild condition for the incorporated glucoamylase. The enzyme exhibited its hydrolyzation function to improve the release rate of rutin by destabilizing the rutin-β-cyclodextrin complex (RCC) in chitosan film. The optimum pH of glucoamylase was achieved with 5 mL addition amount of 0.5 mol/L sodium bicarbonate solution, and the glucoamylase improved the radical scavenging ratio of chitosan film. The yellowness of chitosan film was enhanced with the addition of RCC solution. The films prepared without water demonstrated coarse and rough surface, while the water-based films had smoother and even surface as examined by scanning electron microscopy. In contrast, these observations disappeared in the water immersion groups. X-ray diffraction suggested that the hydrolyzation of β-cyclodextrin and the interlinkage between β-cyclodextrin and the chitosan chain exerted a negative function on maintaining the crystal structure of pure chitosan film. Further, the destabilization of RCC complex with the glucoamylase activity was evidenced by the absence of peak associated with β-cyclodextrin as observed from Fourier transform infrared spectra. The enzyme improved the release of rutin and the addition of RCC successfully endowed antioxidant activity to the chitosan film.

GRAPHIC ABSTRACT

Umbelliferone instability during an analysis involving its extraction process

ABSTRACT

Umbelliferone (7-hydroxycoumarin) is one of the most popular compounds of the coumarins family. This compound receives the attention of scientists due to its diverse bioactivities in a number of applications in various therapeutic fields. An interesting aspect of umbelliferone is its structural lability. The enzymatic degradation process of umbelliferone to its hydroxylated (esculetin), glucosylated (skimmin), and methylated (herniarin) derivatives is already known from the literature. In this paper, we describe the possibility of umbelliferone transformation to other derivatives. We found that eight compounds were formed from umbelliferone during its simulated extraction under reflux performed in different conditions (different heating times and solvents used). Six of them (4,7-dihydroxy-3,4-dihydro-2H-chromen-2-one, 3,7-dihydroxy-3,4-dihydro-2H-chromen-2-one, methyl (2E)-3-(2,4-dihydroxyphenyl)prop-2-enoate, ethyl (2E)-3-(2,4-dihydroxyphenyl)prop-2-enoate, (2E)-3-[2-(acetyloxy)-4-hydroxyphenyl]prop-2-enoic acid, (2E)-3-(2-amino-4-hydroxyphenyl)prop-2-enoic acid) have not been reported yet. Some of these compounds were also identified in extracts of plant materials containing umbelliferone-chamomile flower and cinnamon bark. Compound separation was carried out using the HPLC apparatus. All compounds were identified based on their MS fragmentation paths. The presented results are useful for food producers and consumers, as umbelliferone transformation products can be formed during food product storage, their preparation or processing.

GRAPHICAL ABSTRACT