Sweeteners' Influence on In Vitro α-Glucosidase Inhibitory Activity, Cytotoxicity, Stability and In Vivo Bioavailability of the Anthocyanins from Lingonberry Jams.

Several lines of evidence demonstrate the multiple health-promoting properties of anthocyanins, but little is known regarding the bioavailability of these phytochemicals. Therefore, the stability during storage and bioavailability of anthocyanins from lingonberries jams were determined by HPLC, together with the impact of used sweeteners on their adsorption. Further, the in vitro α-glucosidase inhibition using spectrophotometric methods and cytotoxicity determined on normal and colon cancer cells were communicated. The content of anthocyanins was significantly decreased during storage in coconut sugar-based jam, but was best preserved in jam with fructose and stevia. Fructose and stevia-based jams showed the highest inhibition activity upon α-glucosidase. Lingonberry jams showed no cytotoxic effects on normal cells, but at low concentration reduced the tumor cells viability. Anthocyanins were still detectable in rats' blood streams after 24 h, showing a prolonged bioavailability in rats. This study brings important results that will enable the development of functional food products.

Estimation of degradation kinetics of bioactive compounds in several lingonberry jams as affected by different sweeteners and storage conditions.

Lingonberry fruits are considered to play an important role in nutrition, as they comprise a variety of health-promoting components. Because of lingonberries seasonal availability and also due to their rapid degradation, their stability during processing is a continuous challenge for the food industry. Lingonberries are ideal fruits in making jam due to their natural deep reddish color, but recently, increased demand for low-calorie jams with alternative sweeteners has gained special attention. In this line, the objective of this study was to monitor the changes in anthocyanins, vitamin C, total phenolics, total reducing sugars and antioxidant capacity of several lingonberry jams formulated with different sweeteners (sucrose, fructose, erythritol, brown sugar, coconut sugar, stevia, saccharin). Due to the fact that storage conditions are important factors for jam quality, the jams were stored for 180 days at 4 °C and 25 °C (both under light and dark conditions). The rate constants (k) and the half time values (t1/2) of the degradation processes were determined and degradation kinetics was studied. For all analyzed conditions, first-order reaction kinetics was established for the degradation process of anthocyanins, whereas a second-order kinetic model described the degradation of the other compounds. Kinetic parameters showed that the stability of the studied compounds was highly influenced by the type of sweetener used in jam formulation. Total phenolics and antioxidants were best preserved in the presence of stevia, coconut sugar and fructose, whereas a destabilizing effect of erythritol on vitamin C and anthocyanins content during storage was observed. Among all the studied compounds, anthocyanins presented the fastest degradation, regardless storage conditions. The stability of studied compounds was higher at lower storage temperature (4 °C), while increasing the temperature at 25 °C and exposure to light determined higher rate of the degradation processes. The results provide useful information for understanding some bioactive compounds degradation in real foods, contributing to the development of new food products and providing information of commercial importance.

Sweeteners from Different Lingonberry Jams Influence on Bioaccessibility of Vitamin C, Anthocyanins and Antioxidant Capacity under In Vitro Gastrointestinal Digestion.

Lingonberries are considered anot fully exploited major source of antioxidants. Their health benefits are closely linked to their bioavailability. Due to growing health concerns, consumers are looking for jams prepared with sweeteners other than white sugar, which could be a good alternative to meet their needs. The aim of this research was to evaluate the influence of sucrose, fructose, erythritol, brown sugar, coconut sugar, stevia and saccharine on the bioaccessibility of vitamin C, anthocyanins andthe antioxidant capacity of lingonberry jams under in vitro gastrointestinal digestion. The vitamin C, total anthocyanin content and antioxidant capacity measured by ABTS and FRAP assays were determined spectrophotometrically. Individual anthocyanins were determined by high performance liquid chromatography. All analyzed compounds were highly altered during gastrointestinal digestion and this effect was more visible in the case of the anthocyanins. Antioxidant capacity decreased after gastric digestion, but after the gastrointestinal step, radical scavenging capacity increased, while reducing power decreased. Vitamin C bioaccessibility was negatively affected by coconut sugar addition, while stevia addition showed a protective effect. Fructose and sucrose increased the total anthocyanin stability during the intestinal phase. Stevia, fructose and coconut sugar exhibited high protection of the antioxidant capacity of lingonberry jams during digestion.

Effect of in vitro simulated gastrointestinal digestion on some nutritional characteristics of several dried fruits.

To provide new information on potential health benefits of dried fruits, the effects of in vitro digestion on minerals, total phenolics, total sugars and the antioxidant capacities were evaluated. For the first time, the bioaccessibility of these compounds during in vitro digestion was assessed by multivariate statistical analysis. Although the amount of all minerals decreased after digestion, moderate bioaccessibility was found, excepting Zn. The highest bioaccessibility of phenolics was obtained in prunes and the lowest in dates and cranberries. Total sugars content increased after in vitro digestion of dates, raisins and coconut, but decreased for cranberries, prunes and banana. The in vitro digestion led to an increase in the antioxidant capacity for the majority of dried fruits. The similarities/dis-similarities in pattern of analyzed parameters during digestion was revealed by heat map. Two-way joining cluster and principal component analysis were used to highlight the most relevant parameters in each digestion phase.

The Influence of in Vitro Gastrointestinal Digestion of Brassica oleracea Florets on the Antioxidant Activity and Chlorophyll, Carotenoid and Phenolic Content.

Brassica oleracea L. var. Italica is known to contain a wide variety of antioxidants and due to the protection against various diseases its consumption has been increasing over the years. Thus, knowledge of the changes that occur during the digestion process is of great interest. The aim of this study was to investigate the influence of in vitro gastrointestinal digestion of broccoli on antioxidant activity and on the chlorophyll, carotenoid and phenolic content. First, the ultrasound-assisted extraction of bioactive compounds was optimized and the kinetic model was evaluated. Then, the broccoli was subjected to a static simulated digestion. The antioxidant activity was monitored by ABTS [2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonate)] assay and the contents of target compounds were investigated by UV-Vis spectrophotometry and thin-layer chromatography. The optimum conditions were: solvent-ethanol; time-20 min and temperature-30 °C, and a second order kinetic model was found to describe the mechanism of extraction. The antioxidant activity and carotenoid, chlorophyll and total phenolic content was significantly decreased after simulated gastric and intestinal digestion. The gastric digestion considerably decreased carotenoid and chlorophyll content, meanwhile the intestinal digestion significantly decreased the total phenolic content (TPC). The antioxidant activity was equally affected by both gastric and intestinal digestion.