Recovery of vitamins B from supercritical carbon dioxide-defatted rice bran powder using ultrasound water extraction

Simultaneous analysis of water-soluble and fat-soluble vitamins through RP-HPLC/DAD in food supplements and brewer's yeast

The current study is focused on investigation and quantitation of seven commercially available on the Bulgarian market food supplements, containing multivitamin mixtures of water-soluble and fat-soluble vitamins. In addition, a second fermentation brewer's yeast is also analyzed. The analytical procedures are performed on a RP-HPLC/DAD using Purospher STAR C18 (Merck Millipore, Germany) 5 μm, 25 × 0.46 cm column, conditioned at 25 °C in a column oven. Dionex UltiMate 3000 high performance liquid chromatograph was carried out in diode array detector, set up at 270 nm for water-soluble vitamins, except for vitamin B₅, where 210 nm was applied as analytical wavelength. The fat-soluble vitamins were detected at 325 nm and 265 nm for vitamin A and vitamin E, respectively. Two general methods were developed where Method 1 was based on gradient elution and Method 2 was based on isocratic elution. Both methods identified stated by the manufacturer labeled amounts. The developed methods are applicable for routine analysis of vitamin contents both in multivitamin preparations and in brewer's yeast from secondary fermentation.

Dry-heat processing at different conditions impact the nutritional composition and in vitro starch and protein digestibility of immature rice-based products

Immature grain represents a precious nutritional source in many rural Africa areas. To optimize processing of immature rice into pepeta (a traditional rice-flakes produced from immature rice grains), immature rice (TXD306 variety) harvested at 18 and 26 days after 50% heading were processed in the laboratory under different soaking (0 and 12 h) and roasting temperature (80, 100 and 120 °C) regimes. Riboflavin, nicotinic acid, nicotinamide and iron concentration increased with severity of roasting temperature, while thiamine has an opposite trend. Heating promoted the transformation of insoluble into soluble dietary fiber, increased lipid digestibility decreasing protein one, which showed the highest value when rice was roasted at 100 °C. Soaking before roasting significantly increased moisture and iron content while slightly increased riboflavin, nicotinic acid and nicotinamide when compared to unsoaked products. Among roasted products, starch digestibility increased with roasting temperature. Microstructure analysis indicated a complete loss of cell wall integrity in cooked rice, determining a complete starch and protein digestion while this is delayed in raw rice and roasted products. We concluded that roasting at 100 °C is the optimum temperature to produce pepeta of the highest protein digestibility and low starch digestibility. Soaking before roasting at 120 °C is best when retaining micronutrients is considered.

Enriching street-vended zobo (Hibiscus sabdariffa) drink with turmeric (Curcuma longa) to increase its health-supporting properties

Street-vended foods are cheap, readily available and have been currently identified as possible means for micronutrient fortification in an effort to prevent malnutrition in developing countries. The effect of enriching street-vended zobo drink (Hibiscus sabdariffa) with turmeric (Curcuma longa) was studied to assess the potential to increase health-supporting properties for its consumers. Two processing methods were tested: boiled turmeric root in zobo and addition of fresh turmeric paste to zobo in different concentrations. Vitamin C in turmeric-fortified zobo ranged from 496-725 μg per 100 mL, delphinidin-3-sambubioside from 52-69 mg per 100 mL, and cyanidin-3-sambubioside from 21-27 mg per 100 mL. Micronutrients ranged from 10.9-14 mg L^-1 and 2.19-2.67 mg L^-1 for iron and zinc, respectively. Folic acid, vitamin C, anthocyanins and iron showed the highest amounts in the 2% boiled turmeric zobo samples. Ferulic acid (0.16-2.03 mg per 100 mL), and chlorogenic acid (20-24 mg per 100 mL) did not show the same statistically significant improvement for 2% boiled turmeric-fortified zobo. The zobo samples with turmeric paste consistently had lower values of vitamins, polyphenols and minerals in comparison with the boiled turmeric-fortified zobo samples. Turmeric-fortified zobo can play a role in a healthy diet by its health-supporting properties. Consumption of a typical one serving of 500 mL (representative packaged bottle size of zobo drink by the street vendors in Nigeria) of turmeric-fortified zobo would contribute 63-88% DV and 18-23% DV of iron and zinc. Overall, fortification with boiled turmeric improves the antioxidant and nutritional quality of zobo, specifically regarding vitamin C, delphinidin-3-sambubioside and iron.

Nutritional quality and in vitro digestion of immature rice-based processed products

The nutritional contents of rice decreased as grains matured, and pepeta-type processing improves the nutritional properties and in vitro protein digestibility of rice.

A Review of the Extraction and Determination Methods of Thirteen Essential Vitamins to the Human Body: An Update from 2010

Vitamins are a class of essential nutrients in the body; thus, they play important roles in human health. The chemicals are involved in many physiological functions and both their lack and excess can put health at risk. Therefore, the establishment of methods for monitoring vitamin concentrations in different matrices is necessary. In this review, an updated overview of the main pretreatments and determination methods that have been used since 2010 is given. Ultrasonic assisted extraction, liquid–liquid extraction, solid phase extraction and dispersive liquid–liquid microextraction are the most common pretreatment methods, while the determination methods involve chromatography methods, electrophoretic methods, microbiological assays, immunoassays, biosensors and several other methods. Different pretreatments and determination methods are discussed.

Sequential determination of fat- and water-soluble vitamins in green leafy vegetables during storage

The simultaneous analysis of fat- and water-soluble vitamins from foods is a difficult task considering the wide range of chemical structures involved. In this work, a new procedure based on a sequential extraction and analysis of both types of vitamins is presented. The procedure couples several simple extraction steps to LC-MS/MS and LC-DAD in order to quantify the free vitamins contents in fresh-cut vegetables before and after a 10-days storage period. The developed method allows the correct quantification of vitamins C, B(1), B(2), B(3), B(5), B(6), B(9), E and provitamin A in ready-to-eat green leafy vegetable products including green lettuce, ruby red lettuce, watercress, swiss chard, lamb's lettuce, spearmint, spinach, wild rocket, pea leaves, mizuna, garden cress and red mustard. Using this optimized methodology, low LOQs were attained for the analyzed vitamins in less than 100 min, including extraction and vitamin analysis using 2 optimized procedures; good repeatability and linearity was achieved for all vitamins studied, while recoveries ranged from 83% to 105%. The most abundant free vitamins found in leafy vegetable products were vitamin C, provitamin A and vitamin E. The richest sample on vitamin C and provitamin A was pea leaves (154 mg/g fresh weight and 14.4 mg/100g fresh weight, respectively), whereas lamb's lettuce was the vegetable with the highest content on vitamin E (3.1 mg/100 g fresh weight). Generally, some losses of vitamins were detected after storage, although the behavior of each vitamin varied strongly among samples.