Particle size affects structural and in vitro digestion properties of cooked rice flours

Physico-chemical Characteristics as Indicators of Starch Availability from Milled Rice

Creating high-resistant starch rice by simultaneous editing of SS3a and SS3b.

In this study, we analyzed the differences in metabolites between semiwaxy japonica rice (Yangnongxiang 28 [YNX28]) and conventional japonica rice (Hongyang 5 [HY5]) before and after brown rice milling. The metabolites of brown and milled rice grains from the two rice varieties were analyzed by LC-MS-based nontargeted metabolomics. A total of 266 differentially abundant metabolites (DMs) were tentatively identified in brown rice grains of YNX28 (YNX28B) compared with milled rice grains of YNX28 (YNX28H), and these included 248 upregulated and 12 downregulated DMs. A total of 273 (234 upregulated and 39 downregulated) DMs were tentatively identified in brown rice grains of HY5 (HY5B) compared with milled rice grains of this variety (HY5H). Kyoto Encyclopedia of Genes and Genomes pathway involved and enrichment analyses revealed that 53 and 7 metabolite pathways were enriched and significantly enriched (p<0.05), respectively, in the DMs identified in YNX28B compared with YNX28H, and the main enriched pathways were related to starch and sucrose metabolism, glycerol phospholipid metabolism, arginine and proline metabolism, and glycine, serine and threonine metabolism. Forty-six metabolite pathways were enriched in DMs identified in HY5B compared with HY5H, and these included 16 pathways that were significantly enriched (p<0.05); in addition, the main enriched pathways were related to starch and sucrose metabolism, glycerol phospholipid metabolism, arginine and proline metabolism, and glycine, serine and threonine metabolism. This study provides a theoretical reference for further on the changes in metabolites during rice processing and provides a basis for improving the nutritional quality in rice. PRACTICAL APPLICATION: Original data were obtained regarding the changes of different metabolites in semiwaxy japonica rice and conventional japonica rice before and after processing. The purpose of this study was to investigate the difference of metabolite loss in two rice varieties before and after processing. This paper reports on the differences of metabolites between the two types of japonica rice before and after processing, as well as the changes of key metabolites before and after processing, it also provides important theoretical basis for developing new rice varieties with good nutritional quality.

In vitro starch digestibility of rice flour is not affected by method of cooking

1. A study was set up to investigate the influence of wheat cultivar and wheat crop nitrogen (N) fertilisation on starch (ST) digestion rate in broiler chickens. A total of 288 broiler chickens were used in a 3 × 2 factorial design with diets based on three varieties of wheat (Apache, Caphorn and Charger), each grown at two N application rates (40 and 170 kg of N/ha). 2. Starch digestion rate was determined by measuring the remaining starch and the mean retention time (MRT) in 4 segments of the small intestine (proximal and distal jejunum and proximal and distal ileum) and in excreta, using chromic oxide as a marker. 3. Varietal differences in starch content (714–746 g starch/kg DM) were smaller than differences caused by crop N fertilisation (705–755 g starch/kg DM). Nitrogen application increased wheat crude protein (CP) content from 94 to 130 g/kg DM. 4. The majority of the ST in all diets was digested by the time the digesta reached the distal ileum (average 0·84 in the distal jejunum and 0·96 in the proximal ileum). 5. Starch digestion differed among wheat cultivars in the proximal jejunum (from 0·43 to 0·57, P < 0·001). Afterwards no differences due to wheat cultivar or N fertilisation were found. 6. Starch digestion rate varied among wheat cultivars (from 2·45 to 3·28 h−1, P < 0·001), but did not vary with N fertilisation, whereas dietary CP digestion rate was not affected by wheat cultivar or N fertilisation level. The digestion rate of ST was faster than that of CP (average 2·78 vs. 1·53 h−1). 7. The current study suggests that wheat cultivars can be classified on their rate of ST digestion independently of the N fertilisation applied to the crop during growth.

Rice grain analogues with slow starch digestibility are commonly associated with an unsatisfactory texture, often leading to consumer dissatisfaction. Alginate encapsulation has been applied to reduce the digestibility of corn and potato starch. The fine molecular structures of rice starch can greatly determine its digestibility and texture. However, it remains unclear whether a combination of alginate encapsulation and varied starch molecular structures can be employed to create rice grain analogues that offer both slow starch digestibility and an appealing texture. For the first time, the present study constructed alginate-encapsulated rice beads (as a rice grain analogue). A wide range of starch digestion rates were found among alginate-encapsulated rice beads prepared with different rice varieties, and only certain rice varieties (e.g. Subei and Nanjing) were able to result in rice beads with slower starch digestibility than their parental rice kernels. More importantly, all rice beads showed a relatively softer texture compared to their parental rice kernels. Correlation analysis showed that starch digestion rate, hardness and stickiness were all positively correlated with the ratio of short-range amorphous regions in rice bead samples, as obtained from Fourier transform-infrared spectroscopy, but not with the relative crystallinity. Collectively, these results suggest that rice beads with slower starch digestion rate and softer texture could be obtained by choosing rice varieties that develop more short-range ordered structure after cooking. © 2024 Society of Chemical Industry.

The importance of amylose and amylopectin fine structures for starch digestibility in cooked rice grains

Evaluation of methods for estimating starch digestibility and digestion kinetics in ruminants

Riceberry rice has a dark purple color; and a high content of antioxidants, which could affect the digestion behaviors and its application. This study is aimed to analyze the starch digestion rate and predict the bio-accessibility of polyphenols in various modified Riceberry flours during the in vitro digestive process. It also discussed the relationship between the rate of digestion and polyphenol release, which provided basic information about the digestion behavior of Riceberry flour. Seven rice flour samples were used for this study, which included six physically treated flours: annealed flour (AF), heat moisture-treated flour (HMT), pregelatinized flour (Pregel), ultra-sonicated flour (US), wet microwave-treated flour (Wet), dry microwave treated flour (Dry), and untreated (control sample). The obtained results showed that, compared with the control sample, the digestion rate of the Pregel sample was higher, while the others had lower values. However, the Pregel sample showed the second highest rank of bio-accessible polyphenol during digestion after the US sample. While the HMT sample presented the lowest rate of starch digestion and release of bioactive compounds. This investigation also used an artificial neural network (ANN) to forecast the starch digestion and polyphenol bio-accessibility of rice flours. During digestion, the ANN model demonstrated a high capacity to predict the polyphenol bio-accessibility and starch hydrolysis percentage. There was a goodness of fit between the ANN-predicted and the actual values (R2 &gt;0.95). The importance of the bioavailability and bio-accessibility analysis indicates the functional potential that flour can have, which could be predicted effectively by applying modern techniques such as the ANN model. Moreover, it was also concluded that the digestive tract readily absorbs released polyphenol compounds in rice flour, which also influences the rate of starch hydrolysis. However, the impact could vary depending on the flour’s starch fraction content and the polyphenol activity, which is a topic for future investigation. The high antioxidant content and low digestion rate of flour could be highly promising functional materials for application in the food industry.

Chemical characterisation of marine aerosol at Amsterdam Island during the austral summer of 2006–2007

Single nucleotide polymorphisms in GBBSI and SSIIa genes in relation to starch physicochemical properties in selected rice (Oryza sativa L.) varieties

Aerosol chemical mass closure during the EUROTRAC-2 AEROSOL Intercomparison 2000

Public health implications of rice starch structure-property relations

The nutritive value of two UK wheat varieties. Dean and Beaver, from three different harvest years was assessed. A series of laboratory analysis and animal feeding experiments were conducted to examine the relationship between chemical composition, grain quality, and starch digestibility characteristics and the productive performance of broiler chickens fed wheat-based diets. Differences were observed in the protein content, Hagberg falling number, hardness, particle size and specific gravity between the wheat varieties. Investigations into the nature of the carbohydrate in each sample revealed significant varietal differences in the amount of free glucose and the ratio of amylose to amylopectin in the endosperm. These results indicated that grains from the variety Dean had a harder endosperm texture, contained more starch packed into larger granules that were composed of proportionally less amylose, and had a lower a-amylase activity than Beaver. Feeding experiments using 7-21 day old broiler chickens confirmed varietal differences in broiler growth characteristics and feeding efficiency that were consistent over harvest years. These differences were not related to the apparent or true metabolisable energy values obtained for the experimental diets or the chemical composition of the wheat samples. A significant relationship between feed conversion ratio and Hagberg falling number and between weight gain and specific gravity of the wheat was attributed to improved starch solublisation and the level of starch filling in the grain respectively, and suggested that the nature of the starch may have influenced the growth of the broiler. A relationship between the free glucose content of the wheat and broiler weight gain and feed intake was deemed to be a reflection of varietal differences in Hagberg falling number, and too small a difference to exert an influence on broiler performance. Significant differences in broiler growth due to wheat variety were found in broilers aged from 7-49 days old, confirming that varietal differences in broiler performance occur throughout a typical commercial growing period. Investigations revealed no significant relationship between digesta viscosity and FCR. The digestibility of the wheat samples was examined in vivo, but was of little value as a measure of digestion differences due to high variation in results between individual animals. Large variety differences were observed, however, using an in vitro method that simulated the digestive processes of monogastric animals. These differences were strongly related to the weight gain, feed intake and FCR of the 7-21 day old broilers when the rate of digestion was less than 34 mg/min/100g, although after this point the relationship was random. Multiple regression analysis revealed that only the true metabolisable energy value significantly improved the linear relationship between the rate of starch digestion and broiler weight gain. The relationship between rate of starch digestion and broiler growth was tested as a possible predictive method of wheat nutritional quality using six variety samples harvested in 1994, fed in pellet or meal form, to 7-21 day old broiler chickens. Significant performance differences between the varieties and diet forms were observed, but there were no significant relationships between performance and rate. The in vitro rate of starch digestion method could not therefore be verified as an accurate predictor of nutritive value of wheat for poultry.

Background and objectivesThe objective of this study was to investigate the effects of rice variety, rice material such as flour or cooked grain, and preparation conditions on starch digestibility and textural properties of gels.FindingsRice gels were prepared from cooked‐rice grain via high‐speed shear homogenization or rice flour using five high‐amylose rice varieties. Rice‐flour gels formed a harder and more brittle gel structure than did cooked‐rice gels of the same rice variety. Starch digestion of gels was evaluated using both gels of fixed size and ground gels. The extent of starch digestion for cooked‐rice gels of fixed size negatively correlated with the peak area ratio of DP13‐24 of amylopectin. Starch digestibility was higher in rice‐flour gels compared to cooked‐rice gels of the same rice variety. When using gels of fixed size, a significant correlation was observed between the extent of starch digestion and textural properties.ConclusionsBoth rice variety and processing conditions strongly influenced the textural properties of gels, resulting in the formation of a stronger gel structure and suppression of the extent of starch digestion in rice gels.Significance and noveltyThe combination of both rice variety and processing condition significantly suppresses starch digestibility of rice gels.