Feeding the world’s growing population in a sustainable manner is no easy task. That’s why scientists are exploring options for turning fruit and vegetable byproducts — such as peels or pulp discarded during processing — into nutritious food ingredients and supplements. Now, researchers report in ACS Journal of Agricultural and Food Chemistry showed that blueberry and persimmon wastes can be made into antioxidant-rich powders that may have beneficial effects on gut microbiota.
In recent years, fruit and vegetable powders have become popular as a way to add beneficial compounds such as polyphenols and carotenoids (two types of antioxidants) to the diet, either by consuming the powder directly or as an ingredient in food products. However, in many cases these healthy compounds are present at similar or even higher levels in by-products than in other parts of the fruit or vegetable. Nolia Betoret, Maria José Gossalbes and colleagues wanted to obtain powder from persimmon and blueberry waste and then study how digestion might affect the release of antioxidants and other bioactive compounds. They wanted to determine the effect of digestive powder on the growth of intestinal bacteria.
The researchers obtained the powder from the peel and flower parts of persimmons and from the solids left behind after making blueberry juice. Powder type, drying method, fiber content, and fiber type determine antioxidant release during a simulated digestion. For example, freeze-drying preserves more anthocyanins, but they degrade more easily during digestion than air-dried samples. Then, the team conducted a mock colonic fermentation by adding the powder to a stool slurry and sequencing the bacteria present before and after fermentation. Incubation with fruit powder results in the growth of a variety of beneficial bacteria, and some bacteria grow better with one powder than others. These results indicate that persimmon and blueberry waste powders can be incorporated into food formulations to increase the content of carotenoids and anthocyanins, which may have positive effects on human health, the researchers said.