Rice varieties with a excessive endosperm lipid content material scale back starch digestibility and enhance γ-oryzanol bioaccessibility

According to the Healthy China Initiative, the incidence price of diabetes is 12.8% in China, with about 150 million sufferers, and the incidence price of dyslipidemia is eighteen.6%, with about 160 million sufferers. Common rice has a comparatively excessive proportion of digestible starch and is due to this fact thought-about as a type of meals with a excessive glycemic index (GI). Breeding new types of rice wealthy in resistant starch or slowly digestible starch can meet the wants of “diabetes and obesity” sufferers and make folks maintaining a healthy diet.

On October 28, Prof. WU Dianxing at the Zhejiang University College of Agriculture & Biotechnology and Prof. Fogliano Vincenzo at Wageningen University & Research co-published an article entitled “Rice varieties with a high endosperm lipid content have reduced starch digestibility and increased γ-oryzanol bioaccessibility” within the journal Food & Function.

Lipids have an effect on the style and taste of rice, which is among the causes for making cooked rice so tempting. Lipids play an inhibitory function in starch digestion, however the related mechanism stays unclear. Lipids in rice contains non-starch and starch varieties, with the previous one normally greater than the latter one. In addition, γ-oryzanol as a bioactive compounds is very plentiful in rice in comparison with different cereals. γ-oryzanol is a plant-based mobile melanogenesis inhibitor, and is due to this fact an necessary ingredient of skincare merchandise. γ-oryzanol is normally present in brown rice or rice bran, however hardly ever reported in white rice as frequent rice has an especially low lipids content material in endosperm. Wu and his colleagues obtained rice mutants with excessive resistant starch and excessive endosperm lipids from the mother or father R7954 utilizing the gamma irradiation strategy. This examine revealed the sluggish digestion mechanism and excessive bioaccessibleγ-oryzanol content material of high-lipid rice mutants, indicating the potential of a brand new “low-GI and skin-care” rice.

In their examine, researchers investigated the digestion properties of rice varieties and located that the lipid content material is positively correlated with the resistant starch content material and negatively correlated with the digestion extent and the estimated glycemic index (eGI). After non-starch lipid was faraway from chosen high-lipid mutants (ALK3 and RS4), the digestion extent was considerably enhanced in comparison with native samples when digested by α-amylase, whereas this phenomenon was not noticed in low-lipid rice (GZ93). “These results indicate that rice endosperm lipids inhibited starch digestion, by transforming part of the starch into a slowly digestible starch fraction,” mentioned Wu. “High-lipid mutants also have a higher total amount of, and more bioaccessible, γ-oryzanol than low-lipid varieties. Therefore, high-lipid white rice has great potential in designing functional rice-based foods, combining a relatively lower eGI and a high γ-oryzanol content.”

Provided by
Zhe Jiang University