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•Phytic acid (PA) is generally considered as an antinutrient, though it also plays beneficial role in both plants and animals.•Phytic acid has beneficial as hypoglycemic, antioxidant ...and anti-bacterial agent.•In plant, it helps in seed germination and protect against biotic and abiotic stress.•Fine-tuning of PA can be done by physical, chemical and genetic intervention.
Phytic acid (PA), myo-inositol 1,2,3,4,5,6-hexakisphosphate is the principal storage compound of phosphorus (P) and account for 65%–85% of the seeds total P. The negative charge on PA attracts and chelates metal cations resulting in a mixed insoluble salt, phytate. Phytate contains six negatively charged ions, chelates divalent cations such as Fe2+, Zn2+, Mg2+, and Ca2+ rendering them unavailable for absorption by monogastric animals. This may lead to micronutrient deficiencies in humans since they lack the enzyme phytase that hydrolyzes phytate and releases the bound micronutrients. There are two main concerns about the presence of PA in human diet. The first is its negative impact on the bioavailability of several minerals and the second is the evidence of PA inhibiting various proteases essential for protein degradation and the subsequent digestion in stomach and small intestine. The beneficial role of PA has been underestimated due to its distinct negative consequences. PA is reported to be a potent natural plant antioxidant which plays a protective role against oxidative stress in seeds and preventive role in various human diseases. Recently beneficial roles of PA as an antidiabetic and antibacterial agent has been reported. Thus, the development of grains with low-PA and modified distribution pattern can be achieved through fine-tuning of its content in the seeds.
Recent studies indicate that dietary fibre rich wholegrain foods exhibit low starch digestibility. Hence, resistant starch (RS) content could be an important biochemical marker for slow starch ...digestibility and hence of low glycemic index (GI) and glycemic load (GL). Rice is a starch rich grain. People consuming milled rice as a staple diet and leading sedentary life are likely to develop type-II diabetes in the long run. With rise in the number of diabetics worldwide, one possible approach is to develop rice based low GI foods with high RS content rice, as these show slow starch digestibility and hence would cause only slow rise in postprandial glucose level. In addition to amylose, the linear chains of amylopectin also influence starch digestibility. Starch debranching enzyme pullulanase (PUL) action releases a mixture of linear amylose-like chains that facilitate retrogradation of starch and synthesis of type 3 RS resulting in reduced starch digestibility. Besides mechanical processing, modern technologies like CRISPR have been used to increase amylose and RS (type 5 and type 3) content in rice making it more suitable for diabetics. Phytic acid (PA) chelates Ca++ ions required by intestinal alpha amylase and hence lowers starch digestibility.
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•Resistant starch and amylose are critical indicators for low starch digestibility.•Rice contains type 3 (retrograded) and type 5 (amylose-lipid) resistant starch.•Debranching enzyme pullulanase breaks amylopectin chain to form retrograded starch.•Phytic acid synthesized from glycolytic pathway help in lowering of glycemic index.•Starch digestibility can be regulated by mechanical and molecular approaches.
Lack of appropriate donors, non-utilization of high throughput phenotyping and genotyping platforms with high genotype × environment interaction restrained identification of robust QTLs for grain ...protein content (GPC) in rice. In the present investigation a BC
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mapping population was developed using grain protein donor, ARC10075 and high-yielding cultivar Naveen and 190 lines were genotyped using 40 K Affimetrix custom SNP array with the objective to identify stable QTLs for protein content. Three of the identified QTLs, one for GPC (qGPC1.1) and the other two for single grain protein content (qSGPC2.1, qSGPC7.1) were stable over the environments explaining 13%, 14% and 7.8% of the phenotypic variances, respectively. Stability and repeatability of these additive QTLs were supported by the synergistic additive effects of multi-environmental-QTLs. One epistatic-QTL, independent of the main effect QTL was detected over the environment for SGPC. A few functional genes governing seed storage protein were hypothesised inside these identified QTLs. The qGPC1.1 was validated by NIR Spectroscopy-based high throughput phenotyping in BC
F
population. Higher glutelin content was estimated in high-protein lines with the introgression of qGPC1.1 in telomeric region of short arm of chromosome 1. This was supported by the postulation of probable candidate gene inside this QTL region encoding glutelin family proteins.
•Brown rice is richer in phytic acid (PA) which reduce minerals bioavailability.•Heat processing methods change starch matrix which affects minerals availability.•Expression level of rate-limiting ...enzymes determines PA content in the grain.
Brown rice is superior to milled rice in terms of bioactive compounds and minerals but also has phytic acid (PA) that may reduce the bioavailability of minerals. Further, various household cooking methods of rice also change the starch matrix, affecting mineral availability. The effect of PA and heat processing methods on Fe and Zn bioavailability from milled rice grain was investigated. Rice with contrasting PA was analyzed for Fe and Zn bioavailability in milled and cooked rice. The genotype Khira, with the lowest PA (2.0 g kg−1), exhibited high Fe and Zn bioavailability, while Phalguni, with the highest PA (11.2 g kg−1), showed low Fe and Zn bioavailability. The PA had a significant negative correlation with Fe and Zn bioavailability. Among three common household cooking methods used (pressure cooking, microwave-assisted cooking and boiling), pressure cooking exerted more remarkable effects on mineral bioavailability than other two methods. Screening rice genotypes for low PA and high Fe, Zn bioavailability can solve the problem of micronutrient malnutrition in countries where people depend on rice as the main staple food. The selection of appropriate cooking methods is also helps to enhance mineral bioavailability.
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•Best calibration of NIRS for amylose and protein content of rice.•Development of optimum calibration model in NIRS for proximate compositions of rice bran.•Validation of predicted value with ...reference for all constituents.
With the escalating persuasion of economic and nutritional importance of rice grain protein and nutritional components of rice bran (RB), NIRS can be an effective tool for high throughput screening in rice breeding programme. Optimization of NIRS is prerequisite for accurate prediction of grain quality parameters. In the present study, 173 brown rice (BR) and 86 RB samples with a wide range of values were used to compare the calibration models generated by different chemometrics for grain protein (GPC) and amylose content (AC) of BR and proximate compositions (protein, crude oil, moisture, ash and fiber content) of RB. Various modified partial least square (mPLSs) models corresponding with the best mathematical treatments were identified for all components. Another set of 29 genotypes derived from the breeding programme were employed for the external validation of these calibration models. High accuracy of all these calibration and prediction models was ensured through pair t-test and correlation regression analysis between reference and predicted values.
A large number of short grain aromatic rice suited to the agro-climatic conditions and local preferences are grown in niche areas of different parts of India and their diversity is evolved over ...centuries as a result of selection by traditional farmers. Systematic characterization of these specialty rices has not been attempted. An effort was made to characterize 126 aromatic short grain rice landraces, collected from 19 different districts in the State of Odisha, from eastern India. High level of variation for grain quality and agronomic traits among these aromatic rices was observed and genotypes having desirable phenotypic traits like erect flag leaf, thick culm, compact and dense panicles, short plant stature, early duration, superior yield and grain quality traits were identified. A total of 24 SSR markers corresponding to the hyper variable regions of rice chromosomes were used to understand the genetic diversity and to establish the genetic relationship among the aromatic short grain rice landraces at nuclear genome level. SSR analysis of 126 genotypes from Odisha and 10 genotypes from other states revealed 110 alleles with an average of 4.583 and the Nei's genetic diversity value (He) was in the range of 0.034-0.880 revealing two sub-populations SP 1 (membership percentage-27.1%) and SP 2 (72.9%). At the organelle genomic level for the C/A repeats in PS1D sequence of chloroplasts, eight different plastid sub types and 33 haplotypes were detected. The japonica (Nipponbare) subtype (6C7A) was detected in 100 genotypes followed by O. rufipogon (KF428978) subtype (6C6A) in 13 genotypes while indica (93-11) sub type (8C8A) was seen in 14 genotypes. The tree constructed based on haplotypes suggests that short grain aromatic landraces might have independent origin of these plastid subtypes. Notably a wide range of diversity was observed among these landraces cultivated in different parts confined to the State of Odisha.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The starchy crops which normally form the staple diet of people are rich in carbohydrates. People leading a sedentary lifestyle and consuming high amounts of carbohydrate-rich food normally invite ...obesity and type-II diabetes. Upon digestion of starchy food, postprandial blood glucose level rises rapidly and sharply, which reflects a high glycemic index (GI) value.
Various factors affect starch digestibility and the GI of a food or its products. The internal factors such as amylose, lipid, protein, phytic acid, dietary fibre and resistant starch (RS) have been correlated with lower GI value. The external factors which affect GI and starch digestibility include cooking, processing, retrogradation, soaking and germination. Various food matrices are also responsible for alteration in the GI value. Moreover, changes in the environmental conditions including abiotic and biotic stresses are also responsible for the change in starch structure and composition which ultimately affects GI of starchy crops.
The GI and starch digestibility of foods are affected by intrinsic and extrinsic factors which affect strategies for management of sugar level to ensure better human health. High amylose, RS, lipid and protein in the food were found to reduce starch hydrolysis. Further, retrogradation, various cooking methods and modification of starch by physical and chemical means resulted in lower GI and increased RS considerably. Analysis and management of postprandial blood glucose level while eating starchy crops would help to understand the risk of diabetes and other lifestyle-related diseases.
•The starchy crops are rich in carbohydrates and hence have a high GI value.•High GI food increases the risk of developing diabetes and related diseases.•The GI value can be estimated by in vivo and in vitro methods.•The GI of food is altered by internal, external and environmental factors.•Food processing, cooking, retrogradation and fermentation also affect the GI value.
Parboiled rice is preferably consumed in many countries due to its nutritional superiority and lower starch digestibility. Parboiling affects rice cooking quality, starch digestibility and phytic ...acid which affects minerals bioavailability. Cooking quality was improved in parboiled brown (PB) and parboiled milled (PM) rice. Parboiling has significantly (P < 0.05) reduced glycemic index in both PB and PM rice with a proportionately increase in resistant starch. After milling, the phytic acid (PA) and Fe were reduced significantly (P < 0.05), however, parboiling further reduced PA but increased Fe content and bioavailability in PM rice due to its inward diffusion. Zn content was lower in PB and PM rice due to its outward movement during parboiling. The impact of Zn retention on its bioavailability was insignificant in parboiled rice as non-parboiled rice. This study provides better insights on rice parboiling as a method to reduce starch digestibility and improve mineral bioavailability which could be beneficial for diabetics and malnourished population.
•Rice starch digestibility and mineral bioaavailability were affected by parboiling.•Parboiling lowered the glycemic index with increase in resistant starch content.•Parboiling reduced phytic acid with improved Fe and Zn bioavailability.•Pullulanase regulated resistant starch content during the grain filling stage.•MIPS1 and IPK1 regulated phytic acid content in the grain filling stage.
Rice exhibits relatively high glycemic index (GI) value compared to other carbohydrate rich foods. Eating rice as a staple food and leading sedentary life style may lead to obesity and type‐II ...diabetes. National Rice Research Institute (ICAR‐NRRI), Cuttack, India released varieties were analyzed for low GI and high resistant starch (RS) content. Large variations were observed in the GI (57.5–76.4) and RS content (0.28–2.94%) among the varieties. The rice Shaktiman had the lowest GI (57.50) with relatively high RS content (2.11%) while Gayatri had the highest RS (2.94%) with relatively low GI (60.31) value. Addition of pigeon pea to rice resulted in lowering of GI and increased RS content compared to other pulses. Addition of ghee (clarified butter) to rice during cooking resulted in lowering of GI and increase in RS content. The effect was not so pronounced with vegetable oils. Addition of vegetables like fenugreek and cauliflower to rice caused much more lowering of GI as compared to other vegetables. The findings emphasize the importance of identifying and developing rice with low GI and high RS content. This also highlights the importance of formulating food combinations of rice with other edible commodities that suit diabetics.
Rice exhibits a relatively high glycemic index (GI) value compared to other carbohydrate rich foods. National Rice Research Institute (ICAR‐NRRI), Cuttack, India released varieties are analyzed for low GI and high resistant starch (RS) content. Large variations were observed in the GI (57.5–76.4) and RS content (0.28–2.94%) among the varieties.
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