Anthocyanins are high-value compounds, and their use as functional foods and their natural colorant have potential health benefits. Anthocyanins seem to possess antioxidant properties, which help prevent neuronal diseases and thereby exhibit anti-inflammatory, chemotherapeutic, cardioprotective, hepatoprotective, and neuroprotective activities. They also show different therapeutic effects against various chronic diseases. Anthocyanins are present in high concentrations in onion. In recent years, although both conventional and improved methods have been used for extraction of anthocyanins, nowadays, improved methods are of great importance because of their higher yield and stability of anthocyanins. In this review, we compile anthocyanins and their derivatives found in onion and the factors affecting their stability. We also analyze different extraction techniques of anthocyanins. From this point of view, it is very important to be precisely aware of the impact that each parameter has on the stability and subsequently potentiate its bioavailability or beneficial health effects. We present up-to-date information on bioavailability, dietary effects, and health implications of anthocyanins such as antioxidant, antidiabetic, anticancerous, antiobesity, cardioprotective, and hepatoprotective activities.

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The experiments were conducted to evaluate the impact of air temperature and microwave power level on drying behavior and quality of beetroot. The osmotically pretreated samples in sugar-salt mixed solution were further dehydrated using convective tray drier upto a moisture content of 40 to 60% db (the point where drying rate became slow) followed by microwave drying to a moisture content of 6% (bone dry conditions) to overcome the slow removal of moisture content in the end. Three levels of air temperature 55, 65 and 75°C and microwave power 540,810 and 1080 W each were selected and readings on moisture content, rehydration ratio, color, total soluble solid, water activity and hardness were taken. The results showed that osmotic pretreatment prior to hot air microwave finish drying improved the final quality of dehydrated sample. The drying took place in the falling rate drying period regardless of the drying conditions. Drying at high air temperature (75°C) followed by high microwave power (1080 W) witnessed increased drying rates and substantial shortening of the drying time. Two term and logarithmic model successfully described the drying kinetics of convectively dehydrated and microwave finish dehydrated beetroot slices respectively. Rehydration characteristics of beetroot were improved for samples dehydrated at 55°C and 1080 W, which helped in reduction of shrinkage and case hardening. A greater change in color resulted due to decreased L and b values and increased 'a' value with increase in both air temperature and microwave power. Sample dehydrated at high air temperature followed by high microwave power exhibited high water activity, high total soluble solids (TSS) and improved hardness as compared to fresh sample.

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Coriander (Coriandrum sativum L.) is a highly perishable crop with a shelf-life of a few days under refrigerated conditions. Solar drying is one of the economical, hygienic and eco-friendly methods of food preservation. During this study, fresh coriander was pre-treated in a solution of 0.1% magnesium chloride, 0.1% sodium bicarbonate and 2.0% KMS for 15 min before solar or open sun drying.