According to researchers at North Dakota State University, increased utilization of local staple crops, such as sorghum, sweet potato and yam, can benefit farmers and local economies. These crops can be used for the production of composite flours and other unique food products, such as gluten-free cakes and pastries.
To support the development of such products, the researchers decided to study the functional characteristics of different yam flours. Specifically, they compared the physical and chemical properties of fermented (brown) yam flour and unfermented (white) yam flour with those of refined wheat flour. They reported their findings in an article published in the Journal of Food Processing and Preservation.
Based on multiple analyses, the researchers found that compared with refined wheat flour -- which has been stripped of most of its nutrient content due to processing -- yam flours contain less protein (3.3 to 5.9 percent), arabinoxylans (0.93 to 1.40 percent), the antinutrient phytic acid (0.17 to 0.53 mg/g), phenolic acids (0.57 to 2.28 mg ferulic acid equivalent [FAE]/g), amylose (17.3 to 22.6 percent) and fat (0.2 to 0.4 percent). However, yam flours contain higher amounts of potassium (119 to 845 mg/100 g), ash (1.70 to 2.21 percent), total starch (73.8 to 74.2 percent) and dietary fiber (6.8 to 7.0 percent).
The researchers also reported that while all the samples exhibited high (>90) estimated glycemic index (eGI) values, brown yam flour and white yam flour had significantly lower eGI values than refined wheat flour. This means that both yam flours are less likely to cause blood sugar spikes after consumption than refined wheat flour. Thermal studies, meanwhile, showed that yam flours require more energy for gelatinization, suggesting that the former will take more time to get cooked than refined wheat flour.
On the other hand, brown yam flour is able to swell and retrograde more rapidly than refined wheat flour, meaning it can absorb more liquid than the latter. It also has a significantly higher gel firmness than even white yam flour, which makes it more suitable for certain culinary applications, such as in the making of bread. The researchers thus concluded that all three flours exhibit different characteristics that can impact their functional and nutritional properties.
Yam is a type of tuber vegetable that's often mistaken for sweet potato. But unlike the latter, the former tastes less sweet and is starchier. Depending on its maturity, the color of yam flesh can range from white and yellow (young) to purple or pink (mature).
A superfood in its own right, yam is rich in essential nutrients. A one-cup (136 g) serving of freshly baked yams can provide the following: (h/t to Healthline.com)
Here are some of the health benefits of eating yams: (Related: Compounds in yam have vasodilating and antioxidant properties.)
Yams are versatile and nutritious, and they make perfect additions to a healthy diet. Yams are also great for people with diabetes and weight watchers because of their high fiber content. Get to know more about yams and similarly nutritious foods at Superfoods.news.