Understanding the aggregation structure, digestive and rheological properties of corn, potato, and pea starches modified by ultrasonic frequency.

Corn starch (CS), potato starch (PtS), and pea starch (PS) were modified by ultrasonic frequency (codes as UFCS, UFPtS and UFPS), and changes in aggregation structure, digestibility and rheology were investigated. For UFCS, the apparent amylose content and gelatinization enthalpy (∆H) decreased, while the R1047/1022 values and relative crystallinity (RC) increased under lower ultrasonic frequencies (20 kHz and 25 kHz). For UFPtS, the apparent amylose content, R1047/1022 values and RC increased, while the ∆H decreased under a higher ultrasonic frequency (28 kHz). For UFPS, the apparent amylose content, R1047/1022 values, RC, ∆H decreased at 20 kHz, 25 kHz and 28 kHz. Cracks were observed on the surface of UFCS, UFPtS and UFPS. These aggregation structure changes increased the resistant starch content to 31.11% (20 kHz) and 26.45% (25 kHz) for UFCS and to 39.68% (28 kHz) for UFPtS, but decreased the resistant starch content to 18.46% (28 kHz) for UFPS. Consistency coefficient, storage modulus, and loss modulus of UFCS, UFPtS and UFPS increased, while the flow behavior index and damping factor decreased. Results indicated that CS, PtS and PS had diverse digestion and rheology behaviors after ultrasonic frequency modification, which fulfilled different demands in starch-based products.

Changes in structural, digestive, and rheological properties of corn, potato, and pea starches as influenced by different ultrasonic treatments.

Ultrasound was widely used in starch modification, whereas there was no review focusing on the effects of different ultrasonic treatments on A-, B- and C-type starches. In this study, the effects of ultrasonic power (UP, 100-600 W) and ultrasonic time (UT, 5-35 min) on structural, digestibility and rheology of corn starch (CS), potato starch (PtS), and pea starch (PS) were investigated. As a result, UP and UT decreased the apparent amylose content of CS and PS, while increased the apparent amylose content of PtS. UP and UT enhanced R1047/1022 values of CS, whereas those of PtS and PS were decreased. Moreover, UP and UT decreased the gelatinization enthalpy of CS, PtS and PS. In vitro digestion revealed that UP and UT decreased the resistant starch content of PtS and PS, but increased the resistant starch content of CS. Rheological tests indicated that UP and UT decreased the flow behavior index of CS, PtS and PS pastes, and caused an increase in storage modulus and loss modulus. Results revealed that ultrasonic treatment represented a promising technology to obtain CS, PtS and PS with tailored digestibility and rheology, which allowed the texture and glycemic response of starch-based products to be adjusted.

Structural changes of A-, B- and C-type starches of corn, potato and pea as influenced by sonication temperature and their relationships with digestibility.

The effect of sonication temperature on the structures and digestion behaviour of corn starch (CS, A-type), potato starch (PtS, B-type), and pea starch (PS, C-type) was investigated. For CS, sonication temperature resulted in a rough surface, decreased apparent amylose content, gelatinization enthalpy and gelatinization degree, increased short-range orders, long-range orders, retrogradation degree and resistant starch content. For PtS, sonication temperature led to a coarser surface with scratches, increased apparent amylose content and gelatinization degree, decreased short-range orders, long-range orders, gelatinization enthalpy, retrogradation degree, and resistant starch content. For PS, sonication temperature showed partial disintegration on surface, increased gelatinization degree, decreased apparent amylose content, short-range orders, long-range orders, gelatinization enthalpy, retrogradation degree and resistant starch content. This study suggested that starch digestion features could be controlled by the crystalline pattern of starch used and the extent of sonication temperature, and thus were of value for rational control of starch digestion features.

Long-term functional maintenance of primary human hepatocytes in vitro.

The maintenance of terminally differentiated cells, especially hepatocytes, in vitro has proven challenging. Here we demonstrated the long-term in vitro maintenance of primary human hepatocytes (PHHs) by modulating cell signaling pathways with a combination of five chemicals (5C). 5C-cultured PHHs showed global gene expression profiles and hepatocyte-specific functions resembling those of freshly isolated counterparts. Furthermore, these cells efficiently recapitulated the entire course of hepatitis B virus (HBV) infection over 4 weeks with the production of infectious viral particles and formation of HBV covalently closed circular DNA. Our study demonstrates that, with a chemical approach, functional maintenance of PHHs supports long-term HBV infection in vitro, providing an efficient platform for investigating HBV cell biology and antiviral drug screening.