SCIENCE OF RICE

 

Grain: Husk, bran (brown rice), germ, Endosperm

Husk is inedible layer for human beings

Bran is highly nutritious and has fat layer hence has shorter shelf life as it goes rancid quickly

Endosperm is once bran is removed, there’s only white starchy part left which as high shelf life. 

White rice is made of starch foods mostly and has two kind of starch molecules amylose and amylopectin. Amylose is smaller linear molecule and amylopectin is larger and branched out.  When water and heat is applied amylose breaks through to form a gel like substance. Rice varieties with less than 20% amylose tend to become little sticky after cooking, while varieties with more than 20 % amylose tend to have separate grains post cooking.

Tip: Parboiling method is used to enrich the nutrition of the endosperm, as it drives good amount of nutrients found in bran and germ into the endosperm, hence parboiled rice is almost as nutritious as brown rice.

Gelatinization: Starch molecules break down and form a hard and waxy texture from amylose and sticky gooey texture from the amylopectin.

Retrogradation: Increased firmness and recrystallization of gelatinized starch gels with time.

The cooling of rice after cooking causes retrogradation of starch which becomes a non-absorbable product in human digestive tract. Hence, this method is applied for diabetic cooking. Cooling of cooked starch products decreases the content of available carbohydrates by producing resistant starch. The crystallized starch form can resist enzymatic degradation in small intestine thus lowering the concentration of digestible starch in cooked starch products.

Brown rice possesses high contents of a variety of nutrients, such as fiber, vitamins, and minerals that are lost during the process of refining and milling in the production of white rice. Brown rice possesses four times as much dietary fiber as white rice. 

The rice bran of whole grain brown rice (unpolished) has been acknowledged as a potential source of edible oil. Rice bran oil presents a positive fatty acid profile along with the presence of other phytochemicals. Basically, rice bran is rich in carbohydrates (34–62%), lipids (15–20%), proteins (11–15%), and dietary crude fiber (7–11%). The health benefits of rice bran include the strong antioxidant potential of rice bran oil.

The protein content present in rice bran of brown rice is characterized as a good source of protein that is nutritionally superior and hypoallergenic in nature. Rice bran is a rich source of essential amino acids such as lysine, which seems to be present in minute quantities in other cereal grains. The proteins in rice bran are highly digestible and can be utilized as an effective food ingredient.

White rice is a major source of energy nourishment for the world’s population, especially in Asian countries. However, the carbohydrate content in white rice accounts for 80% of its makeup, which is considered a higher amount than wheat. there are concerns that white rice possesses a high glycemic content and that it may not be a suitable source of carbohydrates for people who have weight problems.

References: Dejkriengkraikul, Pornngarm & Semmarath, Warathit & Mapoung, Sariya. (2019).  Anthocyanins and Proanthocyanidins in Natural Pigmented Rice and Their Bioactivities                                                                                                                                                                         Masala Lab (2020)