Scientists find that vegetable and fruit trimmings often contain more fibre than the edible parts

What the measurements showed

Scientists at King's College London compared the dietary fibre content in different parts of 12 common vegetables and fruits — among them butternut squash, bell pepper, broccoli, kiwi, pineapple, watermelon and fennel. The study was published in the International Journal of Food Sciences and Nutrition, as reported by Gazeta.Ru.

Key findings

Parts that are usually discarded — peels, seeds, trimmings — made up 25 to 48% of the total weight of the produce. In 10 out of 12 cases, it was these parts that contained more fibre per equal weight than the conventionally edible parts. Watermelon rind was found to contain 2.1 g of dietary fibre per 100 g, while the peel and seeds of butternut squash contained 9.25 g per 100 g. The most noticeable difference was in the pineapple: the peel and core together contained roughly 5.5 times more fibre than the flesh.

Exceptions and limitations

The pattern was not universal: in broccoli, the stems contained about 28% less dietary fibre than the florets, and fennel was also an exception. The authors believe that making fuller use of the edible parts of plants could simultaneously increase fibre intake and reduce food waste — for example, through culinary solutions using stems and seeds that are usually thrown away. At the same time, the researchers emphasise that using each part requires a separate assessment of its edibility and safe preparation, and that the study measured the composition of the products, not the effect of eating trimmings on human health.