Use of Protein Content, Amylose Content, and RVA Parameters to Evaluate the Taste Quality of Rice

Taste quality of rice is the key to its value. However, it is greatly affected by rice types and the environment. It is a complex but necessary factor to accurately evaluate the taste quality of various types of rice in different environments. In this study, 7 different types of rice with different taste values were used as materials, and 12 nitrogen fertilizer treatments were applied to obtain 84 different rice taste values. We used protein content, amylose content, and RVA to evaluate changes in the taste value of rice. Rice with high taste value tended to have higher amylose content, peak viscosity, hold viscosity, final viscosity, and breakdown, as well as lower protein content, pasting temperature, and peak time. Protein and amylose contents affected the taste value of rice by affecting the RVA profiles except for setback. For high and low taste-value rice types, protein content could explain 66.8 and 42.9% of the variation in taste value, respectively. In the case of medium taste-value type, protein content was not enough to evaluate the taste quality of rice. Stickiness could explain 59.6% of the variation in taste value. When the protein content of rice was less than 6.61% or greater than 9.34%, it could be used to reflect the taste quality of rice. When the protein content was in between the two, protein content was not enough to reflect the taste quality of rice. Our results suggested that protein content could better reflect the taste quality change for rice, which provided a theoretical and technical basis for the accurate evaluation of the taste value of various types of rice.

Effect of Gamma-irradiation on the Physicochemical, Functional, and Antioxidant Properties of Unpigmented Brown Whole Rice Flour

Whole grain brown rice, being a rich source of fiber and other bioactive compounds like polyphenols is effective in reducing the risk of chronic diseases including cardiovascular diseases, hypercholesterolemia and Type II diabetes. The study was aimed to evaluate the effect of gamma irradiation on the physicochemical, functional and antioxidant properties of whole grain brown rice flour. The brown rice flour was conditioned to two different moisture contents of 10% and 12% and treated with gamma irradiation doses of 0 kGy (native or control), 2.5 kGy and 5 kGy. Moisture, protein, fat, ash and carbohydrate content of native flour was found as 10 g/100 g, 6.54 g/100 g, 1.54 g/100 g, 1.0 g/100 g, and 81.48 g/100 g, respectively. The hunter color ‘L’, ‘a’, and ‘b’ values of the native brown rice flour sample were found as 81.95, −0.97 and 17.36, respectively and were non-significantly ( p ≥ 0.05) affected by gamma irradiation. Apparent amylose content was observed to decrease significantly ( p ≤ 0.05) from 29.97 to 20.30 g/100 g with the increase in gamma irradiation dose and moisture content. The pasting properties such as peak viscosity, trough viscosity and final viscosity of all the flour samples decreased significantly ( p ≤ 0.05) with the increase in irradiation dose. The functional properties such as water and oil absorption and emulsion capacities were increased while emulsion stability and foaming stability decreased upon irradiation. Irradiation led to an overall increase in the antioxidant activity of rice flours. In general, FTIR spectra revealed a decrease in the absorption intensities of the functional groups. Therefore, it can be concluded that gamma irradiation can be used as a tool to modify the physicochemical properties of rice flours as well as to improve their antioxidant properties.

Fertilizer Deep Placement Significantly Affected Yield, Rice Quality, 2-AP Biosynthesis and Physiological Characteristics of the Fragrant Rice Cultivars

The management of fertilizers in a context of climate change and the preservation of the environment is strongly related to the regulation and accumulation of 2-acetyl-1-pyrroline (2AP) in fragrant rice. However, the feasibility of such management strategies in terms of enhancing the accumulation of 2AP has not yet been explored in aromatic cultivars. Here, we investigated the impact of the application of two fertilizers at three depth (surface, 5 cm and 10 cm) levels of placements to improve the aromatic rice quality, including such aspects as the 2AP content-, protein-, amylose- and yield-related traits. For this purpose, two known rice cultivars, Basmati 385 (B-385) and Yunjingyou (YJY), were grown in pots during 2019 and 2020 under fluctuating climates. The deep application of fertilizer at 10 cm significantly affected the 2AP content with such values as 127.53 μg kg−1 and 111.91 μg kg−1 obtained for Fragrant Fertilizer (FF) and Urea in B-385 cultivar, and 126.5 μg kg−1 and 114.24 μg kg−1 being observed for FF and Urea in YJY, respectively, during 2019. In addition, values of 108.41 μg kg−1 and 117.35 μg kg−1 were recorded for FF and Urea in B-385, while 125.91-μg kg−1 and 90.71-μg kg−1 were measured for FF and Urea in YJY, respectively, during 2020. Similarly, B-385 had better 2AP content and yield-related traits, as well as amylose content and cooked rice elongation, as compared to the YJY rice cultivar. The 2AP accumulation and its related biochemical parameters, and their relationships in different plant tissues at different growth stages under FF and Urea treatments, were also improved. Further, the 2AP content and the P5C activity demonstrated strong correlations during the grain filling periods in both fragrant rice cultivars. In conclusion, our findings have the potential to provide useful information to farmers and agriculture extension workers in terms of the saving of fertilizers and the improvement of rice grain quality under fluctuating climate conditions.

Elucidation of Genetic Parameters Controlling Yield and Quality Traits in Rice (Oryza sativa L.)

Background: Forty two crosses involving seven lines and six testers were studied for economically important yield contributing and quality traits to test the magnitude of genetic components and diversity. Formulation of efficient breeding methodology is possible by targeting the genetic architecture of genotypes. Methods: The systematic breeding programme involves generating genetic variability besides sorting off the diverse genotypes and utilizing the extreme phenotypes for producing stable varieties. Genetic diversity helps to achieve the greater continuum of genetic variability in segregating populations to reach for ideal selection of progenies. Heritability and genetic advance are other important selection parameters for retrieving better genotype through selection. Result: Significant differences in analysis of variance were recorded for all the traits. The results signified the greater value of phenotypic coefficient of variation (PCV) than genotypic coefficient of variation (GCV) and environment coefficient of variation (ECV) pertaining to the test traits studied. Among agronomical characters, the GCV and PCV were reported to be in higher estimate for number of productive tillers per plant, number of grains per panicle, single plant yield and among quality characters for gelatinization temperature (GT), length breadth (LB) ratio, gel consistency and amylose content. The present study adverted that among the yield and grain quality characters viz., number of productive tillers, number of grains per panicle, single plant yield, plant height, 1000 grain weight, milling percentage and grain length could be easily inherited to next generation due to high heritability. Whereas breadth elongation ratio and linear elongation ratio are influenced by environmental factors due to their low heritability. Further, the number of productive tillers, number of grains per panicle, single plant yield, plant height, Gel consistency and amylose content exhibited higher PCV, GCV, heritability and genetic advance and hence direct selection can be made for target traits.

Estimated glycemic index of rice increases with the release of new varieties in the middle reach of the Yangtze River

The amylose content of newly-released rice varieties has steadily decreased in rice-growing regions in the middle reach of the Yangtze River during 2006–2021, to parallel increasing consumption of soft-textured rice with low amylose content. We estimated the glycemic index of these newly-released rice varieties and reveal a significantly increasing trend, showing a 0.3 annual increase in estimated glycemic index of new rice varieties released each year. These results highlight the need to assess the potential health risks associated with the development of soft-textured rice with low amylose rice.

Targeted Deletion of the First Intron of the Wxb Allele via CRISPR/Cas9 Significantly Increases Grain Amylose Content in Rice

Background The rice Waxy (Wx) gene plays a major role in seed amylose synthesis and consequently controls grain amylose content. Wx gene expression is highly regulated at the post-transcriptional level. In particular, the GT/TT polymorphism at the 5′splicing site of its 1st intron greatly affects this intron’s splicing efficiency and defines two predominant Wx alleles, Wxa and Wxb. Wxa rice often harbours intermediate to high amylose contents, whereas Wxb rice exhibits low to intermediate amylose contents. By deleting the Wx 1st intron using CRISPR/Cas9 technology, we generate a completely novel Wx allele and further investigate how intron removal affects Wx gene expression and rice grain amylose content. Results CRISPR/Cas9-mediated targeted deletion of the Wx 1st intron was performed on 4 rice inbred lines: KY131 (Wxb), X32 (Wxb), X35 (Wxa) and X55 (Wxlv). Deletion of the 1st intron occurred in 8.6–11.8% of the primary transformants of these 4 inbred lines. Compared to wild-type plants, amylose content was significantly increased from 13.0% to approximately 24.0% in KY131 and X32 mutant lines, which both carried the Wxb allele. However, no significant difference in amylose content was observed between wild-type plants and X35 and X55 mutant lines, which carried the Wxa and Wxlv alleles, respectively. Wx gene expression analysis of wild-type plants and mutants yielded results that were highly consistent with amylose content results. KY131 and X32 mutants accumulated increased levels of steady mRNA transcripts compared with wild-type plants, whereas steady mRNA levels were not altered in X35 and X55 mutants compared with wild-type plants. Grain quality, including appearance quality and eating and cooking quality, which are tightly associated with amylose content, was also assessed in wild-type and mutant plants, and data were presented and analysed. Conclusions This study presents a novel and rapid strategy to increase amylose content in inbred rice carrying a Wxb allele. Our data strongly suggest that the 1st intron of the Wx gene regulates Wx gene expression mainly at the post-transcriptional level in rice. This finding is in contrast to a previous hypothesis suggesting that it influences Wx gene transcription. In addition, removal of the first intron generates a completely novel Wx allele. Further studies on this new Wx allele will provide invaluable insights into the regulation of Wx gene expression, which will help researchers engineer new Wx alleles to facilitate the breeding of rice cultivars with better eating and cooking quality.

Quasi Emulsion Solvent Diffusion Modification of Underutilized Chenopodium album Starch and its Characterization

The present study was designed to investigate the changes occur on Chenopodium album starch (CAS) after modification through quasi emulsion solvent diffusion (QESD) method. Modification of starch was carried out by HCl (0.1, 0.25, 0.50, 0.75 and 1M) followed by precipitation. The QESD modification significantly reduced the amylose content, water absorption capacity, oil absorption capacity, solubility as well as swelling power of treated starch. Gelatinization behaviour of modified starch showed an increase in pasting temperature. The SEM images showed the formation of regular and spherical shaped larger starch particles. There was an improvement in crystallinity from 20.01 to 29.86% after modification as shown in X-ray analysis. Overall, it indicates that QESD treatment results into formation of spherical crystalline agglomerates.

The Effect of Mocaf Substitution on Crispness and Organoleptic Quality of Milk Sticks

Milk sticks are one of the dairy products that are served in the form of snacks. One of the ingredients added in making milk sticks is wheat flour which has a high amylose content. It causes the resulting milk sticks to be less crunchy. It is necessary to substitute flour with low amylose content, namely mocaf (Modified Cassava Flour). This research objective was to determine the effect of mocaf on the level of crispness and organoleptic quality of milk sticks. Milk sticks was made in animal science laboratory UNISKA Kediri by adding different percentage of flour: P0 (100% wheat flour), P1 (90% wheat flour and 10% mocaf), P2 (80% wheat flour and 20% mocaf), P3 (70% wheat flour and 30% mocaf), and P4 (60% wheat flour and 40% mocaf) in six replications. This research using completely randomized design (CRD). These results indicated that the substitution of mocaf in the manufacture of milk sticks could reduce the moisture content of the milk sticks so that the substitution of mocaf could increase the crispness. The organoleptic assessment was carried out on the parameters of color, taste, and crispness. There were no significant differences between the color and taste parameters, while the crispness showed that P0 was not significantly different from P1, but it was significantly different from P2, P3, and P4.

Deciphering the effect of different nitrogen doses on grain protein content, quality attributes and yield related traits of rice

Understanding the gravity of nutritional significance of rice (Oryza sativa L.) protein, an experiment conducted in Randomized Complete Block Design (RCBD) involving effect of nitrogen (N) rates i.e.,140 kg N/ha, 120 kg N/ha, 100 kg N/ha and 80 kg N/ha on grain protein content, yield parameters and cooking characteristics of polished rice from eight rice genotypes was conducted. N application significantly affected the grain protein content, grain yield, head rice recovery, plant height and effective tillers. In high protein cultivars substantially low to intermediate amylose content and more cooking time was recorded while in low protein counterpart amylose content was comparatively high with low cooking time. Maximum cooking time in polished rice was of 25 min at 180 kg N/ha dose and highest amylose content of about 27% at 80 kg N/ha. Gumminess and hardness of cooked rice and cooking time significantly elevated with increase in N dose. The substantial differences in grain protein content in brown, polished and cooked rice was observed. Cooking revealed the significant increase in protein content ranged from 50%-70% in low protein to high protein genotypes. R-RGM-ATN-47 with highest grain yield of 62.13 q/ha, grain protein content of 10.00 % in polished rice and intermediate amylose appears to be the most promising candidate.