Development of β‐carotene loaded nanoemulsion using the industrial waste of orange ( Citrus reticulate ) peel to improve in vitro bioaccessibility of carotenoids and use as natural food colorant

Abstract Converting waste to valuable products is increasingly getting attention in recent years. After extraction of juice in many fruits, the peel goes as waste. Herein, we have used orange ( Citrus reticulate ) peel waste to extract β‐carotene. The extracted β‐carotene was used to develop a stable nanoemulsion (NE) using a VXX750 ultrasonic homogenizer (Sonics & Materials, USA) to use as a natural colorant in food products. The droplet size and surface charge of developed NE were 143.7 nm and −38.2 mV. The addition of NE to the fruit juice significantly enhances its color, thus providing an alternative to the use of synthetic color. The NE further increases the β‐carotene bioaccessibility and also retinol activity equivalent (RAE) in the fruit juice. Analysis of the Citrus reticulata peel extract was done using UV–Vis spectrophotometer and HPLC. The quantity of β‐carotene extracted from Citrus reticulata peel was 23.57 μg/gm and total carotenoid content was 27.61 μg/gm. Practical applications Generating value added products from waste is the need of the hr for sustainable development and lowering environmental pollution caused by dumping the food waste. We have developed a β‐carotene loaded NE from the waste of orange peel to act as natural food color as well as to increase the bioaccessibility of β‐carotene increasing the nutritional value of the juice. After addition of the nanoemulsion, bioaccessibility of β‐carotene and retinol activity equivalents (RAE) significantly increased. We have further used it as natural food colorant providing alternative to the synthetic food color.