Biogenic nanoparticles from waste fruit peels: Synthesis, applications, challenges and future perspectives.

Nanotechnology is a continually growing field with a wide range of applications from food science to biotechnology and nanobiotechnology. As the current world is grappling with non-biodegradable waste, considered more challenging and expensive to dispose of than biodegradable waste, new technologies are needed today more than ever. Modern technologies, especially nanotechnology, can transform biodegradable waste into products for human use. Researchers are exploring sustainable pathways for nanotechnology by utilizing biodegradable waste as a source for preparing nanomaterials. Over the past ten years, the biogenic production of metallic nanoparticles (NPs) has become a promising alternative technique to traditional NPs synthesis due to its simplicity, eco-friendliness, and biocompatibility in nature. Fruit and vegetable waste (after industrial processing) contain various bioactives (such as flavonoids, phenols, tannins, steroids, triterpenoids, glycosides, anthocyanins, carotenoids, ellagitannins, vitamin C, and essential oils) serving as reducing and capping agents for NP synthesis and they possess antibacterial, antioxidant, and anti-inflammatory properties. This review addresses various sources of biogenic NPs including their synthesis using fruit/vegetable waste, types of biogenic NPs, extraction processes and extracted biomaterials, the pharmacological functionality of NPs, industrial aspects, and future perspectives. In this manner, this review will cover the most recent research on the biogenic synthesis of NPs from fruit/vegetable peels to transform them into therapeutic nanomedicines.

Bioavailability and Bioactivity of Selenium from Wheat ( Triticum aestivum), Maize ( Zea mays), and Pearl Millet ( Pennisetum glaucum), in Selenium-Deficient Rats.

This study examined the bioavailability and bioactivity of selenium (Se) from staple cereals, wheat, pearl millet, and maize, in Se-deficient rats (Wistar strain (OUT-Wister, IND-cft (2c)). The bioavailability and bioactivity of Se were determined by measuring the Se contents of the tissue and organs and activities of Se-dependent enzymes. Se-deficient rats were repleted with Se through wheat, pearl millet, and maize. The wheat diet exhibited the highest bioavailability of Se, followed by pearl millet and maize. The bioactivity of Se, as indicated by the activity of the Se-dependent enzymes, was found to be significantly ( p < 0.001) higher in the organs of rats fed the wheat diet, followed by pearl millet and maize diets. The deficiency of Se resulted in a significant decrease ( p < 0.001) in the activity of antioxidant enzymes in circulation and organs. The staples wheat, pearl millet, and maize have a high bioavailability of Se.

Influence of domestic processing on the bioaccessibility of selenium from selected food grains and composite meals.

Selenium, an ultra trace element with several health beneficial attributes, should be mainly derived from dietary sources. Since food processing is likely to alter the bioavailability of micronutrients, the influence of such processing such as germination and fermentation on selenium content and bioaccessibility, information on which is lacking, was examined in this study. Bioaccessibility of selenium from four cereal-based composite meals was also studied. Chickpea, green gram and finger millet were employed to study the effect of germination, and for effect of fermentation, batters used in preparation dosa, idli and dhokla were used. Soaking the grains in water as a part of germination and fermentation brought about a decrease in selenium content, while its bioaccessibility was not affected. The information on the loss of selenium during soaking and heat processing of the germinated grains is novel. Fermentation resulted in a further decrease in selenium content, the percent decrease ranging from 26 to 47 in the batters. Similar decreases were seen in the bioaccessible selenium content as a result of soaking and fermentation. Cooking of the fermented batters, however, significantly enhanced the bioaccessibility of selenium from dosa and dhokla by 44 and 71 %, respectively. Selenium content of the four meals ranged from 150 to 228.8 ng/g. Bioaccessible selenium was highest in the finger millet-based meal (32.8 ng/g), followed by sorghum, wheat and rice-based meals. The present investigation thus provides vital and novel information on selenium content and bioaccessibility from foods subjected to processing as is commonly practiced in Indian households.

Bioaccessibility of selenium, selenomethionine and selenocysteine from foods and influence of heat processing on the same.

Selenium (Se) is an essential nutrient with diverse physiological functions. The selenium content of commonly consumed cereals, pulses and green leafy vegetables (GLV) was determined. Bioaccessibility of Se, and its organic forms selenomethionine (SeMet), and selenocysteine (SeCys2) was also examined, and the effect of heat processing on the same was studied. The bioaccessibility of Se in cereals ranged from 10% to 24%, that of pulses was between 12% and 29%, and of GLV, 10-31%. The concentration of SeMet in the dialysates of the cereals, pulses and GLV ranged from 5.15 to 28.7, 2.7 to 36.2, and 0.03 to 5ngg(-1), respectively. The concentration of SeCys2 in the dialysates of the foods examined was negligible. Heat processing significantly decreased the bioaccessibility of Se, SeMet and SeCys2. This is the first report on the bioaccessibility of Se and its major organic forms from commonly consumed staples, and the effect of heat processing on the same.

Functional and nutritional evaluation of supplementary food formulations.

Two type of ready to eat supplementary food formulations were developed by roller drying based on wheat, soy protein concentrate, whey protein concentrate, and green gram flour and were fortified with vitamins and minerals to meet the one third of the Recommended daily allowance (RDA). The supplementary food formulations contained 20-21% protein, 370-390 kcal of energy and 2,300 µg of ß-carotene per 100 g serving. The physico-chemical, functional and nutritional characteristics were evaluated. The chemical score indicated that sulphur containing amino acids were the first limiting in both the formulations. The calculated nutritional indices, essential amino acid index, biological value, nutritional index and C-PER were higher for formula II. Rat bioassay showed higher PER (2.3) for formula II compared to formula I (2.1). The bioaccessibility of iron was 23%. Sensory studies indicated that the products were acceptable with a shelf life of 1 year under normal storage condition. However, the formulations were nutritionally better than only cereal based supplementary food formulations available commercially. The product could be served in the form of porridge with water/milk or in the form of small laddu.