8 Apr 2019
Scientists have analysed waste from the orange juice industry to find useful products. The waste was found to have potential applications in the food industry, including as a cheap and sustainable source of fructose and pectin.
The citrus industry is one of the largest fruit industries worldwide. Around 40% of citrus fruit produced is used to make juice, mainly orange, which is produced by an extraction process that results in a total 24.3m tons of waste per year, mainly consisting of the peel, seeds and pulp of the oranges.
The waste from orange juice production can have a negative environmental impact. Not only is it an unsustainable process, the fermentation of waste products has a high chemical and biological oxygen demand.
Orange juice waste is currently used in a variety of ways. The orange peel can be used as a source of essential oils, sugars, natural antioxidants, organic acids and pectin. Many of these chemicals are in high demand, particularly antioxidants. The pulp is also dried and used as an animal feed.
Scientists at the Instituto de Investigación en Ciencias de la Alimentación (Research Institute in Food) Science, Madrid, Spain, have analysed waste from orange juice production to identify potential valuable products and develop an improved extraction process.
Their main interest of the work was extracting the polysaccharide, pectin. Pectin is a soluble fibre can be used as a thickener or stabiliser, and is commonly used in jams, desserts, soups and drinks. Consuming pectin can also have beneficial effects in the digestive system.
The researchers also managed to extract high levels of fructose, a sugar that is sweeter than sucrose but with a lower calorie content. The fructose extracted could be used as an ingredient in the food industry.
The extraction process they developed is sustainable, and uses biodegradable materials including enzymes. The team hopes to diversify the way citrus waste is utilised and reduce the negative environmental impacts of the process.
This article was originally published in SCI’s Journal of the Science of Food and Agriculture.