Effect of autoclaving and cooling on resistant starch formation in rice starch

2016 ◽  
Vol 35 (2) ◽  
Author(s):  
Lilia-Baby ◽  
K. T. Suman ◽  
S. Krishnan ◽  
V. Indira

A study was undertaken to standardise processing treatments for optimising resistant starch (RS) formation in rice starch. The effect of processing conditions on the RS content of rice starch was studied in 48 treatments by autoclaving at 121°C and 141°C for 20, 40 and 60 minutes without moisture and with 10, 20 and 40 percentage moisture levels. After autoclaving, the samples were cooled at room temperature and at -20°C. The yield of RS was found to be maximum in samples autoclaved at 141°C for 40 minutes with 10 per cent moisture and cooled at -20°C. Increasing the duration of autoclaving up to 60 minutes at a lower temperature of 121°C was also found to be effective in improving the RS content of rice starch. RS formation not only depends on a single factor but also on multiple factors like time and temperature of autoclaving, moisture as well as cooling conditions.

1994 ◽  
Vol 346 ◽  
Author(s):  
Steven A. Jones ◽  
James M. Burlitch

ABSTRACTProtoenstatite, a high-temperature polymorph of enstatite (MgSiO3), is generally not stable at room temperature, and is difficult to synthesize. Using a recently developed, hydrogen peroxide-assisted, sol-gel synthesis, protoenstatite was synthesized in a form that was stable at room temperature. Its crystallization was strongly dependent on processing conditions, particularly on the manner in which the xerogel was formed and fired. Xerogels prepared by evaporation, sprav-drying and freeze-drying were compared by XRD, HTXRD, BET, TG/DTA, and 29Si NMR methods. When samples were prepared by evaporation or spray-drying, the result was a mixture of polymorphs. Only the freeze-dried precursor yielded protoenstatite at a lower temperature and within a shorter time than any previously reported.


Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 1897
Author(s):  
Hideyasu China ◽  
Nami Kageyama ◽  
Hotaka Yatabe ◽  
Naoko Takenaga ◽  
Toshifumi Dohi

We report a convenient and practical method for the preparation of nonexplosive cyclic hypervalent iodine(III) oxidants as efficient organocatalysts and reagents for various reactions using Oxone® in aqueous solution under mild conditions at room temperature. The thus obtained 2-iodosobenzoic acids (IBAs) could be used as precursors of other cyclic organoiodine(III) derivatives by the solvolytic derivatization of the hydroxy group under mild conditions of 80 °C or lower temperature. These sequential procedures are highly reliable to selectively afford cyclic hypervalent iodine compounds in excellent yields without contamination by hazardous pentavalent iodine(III) compound.


1997 ◽  
Vol 60 (4) ◽  
pp. 527-532 ◽  
Author(s):  
A. Escarpa ◽  
M.C. González ◽  
M.D. Morales ◽  
F. Saura-Calixto

2010 ◽  
Vol 58 (13) ◽  
pp. 8043-8047 ◽  
Author(s):  
Hongxin Jiang ◽  
Junyi Lio ◽  
Mike Blanco ◽  
Mark Campbell ◽  
Jay-lin Jane

2018 ◽  
Vol 68 (3) ◽  
pp. 235-242 ◽  
Author(s):  
Adrian Górecki ◽  
Wioletta Błaszczak ◽  
Jacek Lewandowicz ◽  
Joanna Thanh-Blicharz ◽  
Kamila Penkacik

2021 ◽  
Vol 41 (3) ◽  
pp. 238
Author(s):  
Jhauharotul Muchlisyiyah ◽  
Tri Dewanti Widyaningsih ◽  
Retno Wulansari ◽  
Hera Sisca Prasmita

Coleus tuberosus, also known as black potato, is one of the Indonesian local tubers consumed as a carbohydrate substituent. Therefore, this study aimed to examine the effect of processing and cooling methods on the in vitro digestibility of black potato starch. Furthermore, two factors Randomized Block Design with a 2x3 experimental design was used, which consisted of processing methods (boiling, roasting, and microwave) and cooling at room temperature and 4 °C for 24 hours with 3 repetitions. Black potato flour was compared with the raw form, by assessing some parameters, namely Resistant Starch (RS), Slowly Digestible Starch (SDS), Rapidly Digestible Starch (RDS), and Glycemic Index (GI). Also, the analysis of total starch, moisture, and color was performed, hence raw black potatoes generally have 10% resistant starch (%wb). Different treatments of cooking and cooling had a significant effect (α = 0.05) on moisture content, total starch, RS, RDS, SDS, GI, brightness (L), and yellowness (b). Black potatoes subjected to the processing method followed by cooling had lower RDS and increased RS content. Furthermore, refrigeration at 4°C for 24 hours reduced the digestibility of black potato starch more than cooling at room temperature. Contrarily, microwaved black potato cooled at room temperature showed a higher digestion rate compared to the raw counterpart. Conclusively, processing followed by cooling reduces the GI and increases the RS content of Coleus tuberosus.


2021 ◽  
Author(s):  
Hsi-Chao Wang ◽  
Yu-Chia Hsu ◽  
Yong-Pei Wu ◽  
Su-Ying Yeh ◽  
Maurice S. B. Ku

Abstract Rice is the staple food for half of the world’s population. Starch accounts for 80-90% of the total mass of rice seeds, and rice starch is low in resistant starch (RS) with a high glycemic index (GI). RS has gained important since it is beneficial in preventing various diseases. Starch branching enzyme IIb (SBEIIb) plays a key role in the amylopectin synthesis pathway in the endosperm of cereals. Down-regulation of SBEIIb in several important crops has led to high amylose, high RS and low GI starch. In this study, we mutated OsSBEIIb in the japonica rice cultivar TNG82 through CRISPR/Cas9 and investigated the molecular and physicochemical modifications in OsSBEIIb mutant lines, e.g., gene expression, enzyme activity, apparent amylose content (AAC), RS and GI. As expected, the levels of modification in these starch related traits in heterozygous mutant lines were about half as those of homozygous mutant lines. Gene expression and enzyme activity of OsSBEIIb were down-regulated significantly while AAC and RS contents increased progressively from 17.4% and 0.5% in WT, respectively, to as high as 25.0% and 7.5% in heterozygous mutant lines and 36.0% and 12.0% in homozygous mutant lines. Consequently, with increased RS and decreased rate of reducing sugar production, GI progressively decreased in heterozygous and homozygous mutant rice endosperms by 11% and 28%, respectively. Our results demonstrate that it has huge potential for precise and efficient generation of high RS and low GI rice through CRISPR/Cas9 to provide a more suitable source of starch for type II diabetes.


2019 ◽  
Vol 75 (8) ◽  
pp. 1036-1044 ◽  
Author(s):  
Małgorzata Katarzyna Cabaj ◽  
Roman Gajda ◽  
Anna Hoser ◽  
Anna Makal ◽  
Paulina Maria Dominiak

Crystals of hypoxanthinium (6-oxo-1H,7H-purin-9-ium) nitrate hydrates were investigated by means of X-ray diffraction at different temperatures. The data for hypoxanthinium nitrate monohydrate (C5H5N4O+·NO3 −·H2O, Hx1) were collected at 20, 105 and 285 K. The room-temperature phase was reported previously [Schmalle et al. (1990). Acta Cryst. C46, 340–342] and the low-temperature phase has not been investigated yet. The structure underwent a phase transition, which resulted in a change of space group from Pmnb to P21/n at lower temperature and subsequently in nonmerohedral twinning. The structure of hypoxanthinium dinitrate trihydrate (H3O+·C5H5N4O+·2NO3 −·2H2O, Hx2) was determined at 20 and 100 K, and also has not been reported previously. The Hx2 structure consists of two types of layers: the `hypoxanthinium nitrate monohydrate' layers (HX) observed in Hx1 and layers of Zundel complex H3O+·H2O interacting with nitrate anions (OX). The crystal can be considered as a solid solution of two salts, i.e. hypoxanthinium nitrate monohydrate, C5H5N4O+·NO3 −·H2O, and oxonium nitrate monohydrate, H3O+(H2O)·NO3 −.


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