Bioactive substances and product development of cereals-2 www.immy.cn www.immyhitech.com

Bioactive substances and product development of cereals-3

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Wheat bread made with 15%~20% barley flour is acceptable, but an increase in the proportion of barley flour will cause the bread to shrink in size, harden in texture, and dark brown in color [21]. Wheat noodles made with 12%~25% barley flour have acceptable noodle-making characteristics [22]. Barley tea is widely drunk in Asia, and it is made from roasted barley kernels [23]. The second largest use of barley is malt, which is used in the production of beer, distilled alcohol, malt syrup, malted milk, condiments, and breakfast foods, among others.

With the rapid development of the world's nutritional and health food production, the development and utilization of barley food has attracted the attention of food experts at home and abroad, and is considered to be a hot spot for the development of new foods in a certain period of time in the future.

2.2 Oat products

Oats are eaten in a variety of forms and can be made into a variety of edible products. Internationally, oatmeal is the most common oat food, in China's oat producing areas, oats are often processed into oat flour, also known as noodles, and then make a variety of oat pasta.

Oats are eaten as is, mainly used as porridge and can also be used to mix and make a variety of baked goods such as oatcakes, oatmeal cookies, and oatmeal bread. Oats are rich in dietary fiber, both soluble and insoluble. It's also rich in essential fatty acids like linoleic acid and oleic acid, which help lower LDL cholesterol and HDL cholesterol, and it's also rich in minerals like magnesium, potassium, and calcium, making it a good source of folate, which is needed for cardiovascular health. Oat alkaloids are antioxidants unique to oats, which inhibit the formation of oxygen free radicals. Due to its high fat content, oat flour is sticky and not easily sifted, replacing it with the more common whole-grain oat products – oat rice and oatmeal. The polar lipid moiety of oat oil is suitable for use as an emulsifier [24].

Oat flour is used as an ingredient in a variety of bread and bakery products because of their unique flavor and moisturizing properties in addition to enhancing the nutritional value of these products. In the traditional wheat bread recipe, the addition amount of oats is as high as 10%~20%. By optimizing the baking technique, it is even possible to add more oat flour [25]. Using oats as a matrix, lactic acid bacteria and probiotic drinks can be prepared. The starter culture, oat flour and sucrose content affect the fermentation process. During fermentation and storage, the β-glucan content in the beverage remains the same. This beverage can be stored under refrigerated conditions for 21 days [26].

A novel low-fat mayonnaise can be prepared from oat dextrin with a glucose equivalent of 8.1, a viscosity of 1620 MPa-s, and a calorific value of 597.7 kcal/100 g [27].

2.3 Sorghum products

Sorghum has a higher insoluble fiber content, which leads to a lower rate of hydrolysis of sugar, so sorghum food is more suitable for diabetics. For example, sorghum products have been shown to lower blood sugar levels in diabetics compared to wheat preparations. Biscuits made from sorghum flour are suitable for diabetics, and the raw materials of the biscuits are a mixture of 40% wheat flour and 60% sorghum flour, which is high in fiber. It is well known that the moist heat treatment of sorghum reduces its digestibility.

During processing, starch retrogradation occurs, resulting in the formation of resistant starch and an increase in dietary fiber content [28]. Therefore, tannic sorghum has potential applications in diabetic foods. Tannin sorghum is characterized by slow digestion. Africa's food culture is more skewed towards tannin sorghum because it provides a longer feeling of fullness compared to other grains. Sorghum is gluten-free, and it is also a potential source of nutrients, such as antioxidant phenols and cholesterol-lowering waxes [29].

2.4 Millet products

Millet is an important small grain crop that is mainly cultivated in mainland India and Africa and is one of the oldest cultivated crops in the world. Millet is the main product of millet milled and processed, and it is a traditional grain product that people in China especially like to eat. In recent years, it has become increasingly important due to its nutritional properties. In addition to being a staple food, millet can also be used to make snack foods such as noodles, gummies, and vitamin C. Millet products have a high mineral content, but antinutrients such as phytic acid and polyphenols affect the in vitro digestibility of protein and starch.

Acid-treated millet products are more acceptable than peeled millet products. Millet is mixed with soybeans or other protein-rich products, such as beans or peanuts, to create a nutritionally balanced complementary food. Studies have shown that the protein content of extruded millet products mixed with 30% cereal soybean meal or 15% defatted soybean meal is 14.7% and 16.0%, respectively [30]. Noodle products such as noodles, macaroni, etc., can be made from millet flour. Squeezed snacks made with rice flour, corn flour, or tapioca and millet flour in different proportions are acceptable in appearance, color, and texture.

Millet is rich in oil and linoleic acid, accounting for 4% of the total fatty acids of oil, and its proportion of n-3 fatty acids is higher than that of corn, while linoleic acid in corn accounts for only 0.9% of the total fatty acids. N-3 fatty acids play an important role in physiological functions such as platelet aggregation, LDL cholesterol accumulation, and the immune system [31]. Millet bran contains a high proportion of soluble dietary fiber, which has cholesterol-lowering and hypoglycemic effects.

2.5 Corn products

In addition to being used as human food and animal feed, corn is an important source of a large number of industrial products. Food additives include corn fiber oil, corn cellulose gum, cellulose fiber gel, xylo-oligosaccharides, and ferulic acid, vanillin, and xylitol are also useful by-products. Corn gum can be used as a binder, thickener, or additive in plastics, and corn starch can be used to produce corn syrup, maltodextrin, glucose, and starch [32]. Refined corn oil is 99% triacylglycerin, which includes 59% polyunsaturated fatty acids (PUFAs), 24% monounsaturated fatty acids (MUFAs) and 13% saturated fatty acids (SFAs).

Mendonca et al. [33] found that adding corn bran to extruded snacks at a ratio of 150~320 g/kg could significantly reduce the radial expansion rate, appearance, and general acceptability of the finished product. Holguin Acuna et al. [34] found that corn bran with 300 g/kg and 400 g/kg had the lowest breaking strength, and extrusion could improve the poor properties of corn bran in baked goods. The cellulose fiber gel prepared from corn bran can be used as a fat mimetic for popularization. Corn bran and fiber can also be used as a substrate for the production of xylitol, a low-calorie, non-carcinogenic sweetener.