Effects of palm oil on structural and in vitro digestion properties of cooked rice starches

Effects of limited moisture content and storing temperature on retrogradation of rice starch

The objective of this study is to investigate the effects of limited moisture content and storing temperature on the retrogradation of rice starch. Starch was gelatinized in various moisture contents (30-42%) and rice paste was stored at different temperatures (4 °C, 15 °C, 30 °C, -18/30 °C and 4/30 °C). X-ray diffraction (XRD) analysis revealed that after retrogradation, the crystalline type of rice starch changed from A-type to B + V type. The B-type crystallinity of retrograded rice starch under 30 °C was the highest among the five temperature conditions, and an increase in B-type crystallinity with increasing moisture content was observed. Differential scanning calorimetry (DSC) results revealed that rice starch retrogradation consists of recrystallization of amylopectin and amylose, and is mainly attributed to amylopectin. The higher moisture content was favorable for amylopectin recrystallization, whereas the moisture content had little effect on the amylose recrystallization. The optimal temperature for amylopectin and amylose recrystallization was 4 °C and 15 °C, respectively. The amylopectin recrystallization enthalpy of rice starch stored at 4/30 °C was mediated between 4 °C and 30 °C but always higher than that at -18/30 °C. On the whole, after being heated at 42% moisture content and stored at 4 °C, rice starch showed the maximum total retrogradation enthalpy (8.44 J/g).

Effect of Tara Gum Addition on Steady and Dynamic Shear Rheological Properties of Rice Starch Isolated from the Korean Rice Variety 'Boramchan'

The present study was performed to investigate the influence of tara gum (TG) addition on the steady and dynamic shear rheological properties of rice starch (RS) isolated from the Korean rice variety 'Boramchan' flour. From X-ray diffraction and Fourier transform infrared spectra of RS, it was found that RS was purely isolated. All RS+TG pastes (4.7:0.3, 4.5:0.5, and 4.3:0.7, w/w) showed shear-thinning fluid characteristics. Adding TG significantly increased the values of apparent viscosity and consistency index of RS. In the dynamic shear rheological analysis, the dynamic moduli and complex viscosity of RS+TG pastes were significantly greater than those of the RS paste, indicating that RS+TG pastes had significantly higher viscoelastic properties than the RS paste. Light microscopy images of RS+TG pastes showed that the addition of TG can inhibit the RS granule from swelling.

The Effect of Digestion and Digestibility on Allergenicity of Food

Food allergy prevalence numbers are still on the rise. Apart from environmental influences, dietary habits, food availability and life-style factors, medication could also play a role. For immune tolerance of food, several contributing factors ensure that dietary compounds are immunologically ignored and serve only as source for energy and nutrient supply. Functional digestion along the gastrointestinal tract is essential for the molecular breakdown and a prerequisite for appropriate uptake in the intestine. Digestion and digestibility of carbohydrates and proteins thus critically affect the risk of food allergy development. In this review, we highlight the influence of amylases, gastric acid- and trypsin-inhibitors, as well as of food processing in the context of food allergenicity.