Functional properties and starch digestibility of instant Jasmine rice porridges

Reducing starch digestibility of white rice by structuring with hydrocolloids

Controlling starch digestion in high glycaemic index staple foods such as white rice is of interest as it has been associated with reduced risk for conditions such as obesity and type-2 diabetes mellitus. Addition of hydrocolloids has been proposed to reduce the rate of post-prandial glucose by controlling the rate of starch hydrolysis. In this work, the potential of a range of hydrocolloids to modify starch digestibility when added (at 1 % maximum concentration) during cooking of white rice was first investigated. Low acyl gellan gum (LAG) showed the highest potential (in-vitro estimated Glycaemic Index reduced by about 20 %, from 94 in the control to 78 in the LAG rice) and was investigated further. While the grains of rice control and rice with LAG appeared similar, SEM images revealed a gel-like layer (a few micrometers in thickness) on the surface of the treated samples. Addition of LAG appeared to also have an effect on the breakdown of a simulated cm-sized bolus. During gastric digestion, bolus breakdown of the rice control was completed after 30 min, while the rice LAG bolus appeared intact after 1 h of observation. This was attributed to strengthening of the LAG gel in the acidic environment of the stomach. During intestinal digestion, rice samples containing 1 % LAG appeared to be less susceptible to breakdown when seen under a microscope and in environmental SEM, while they showed larger rice particle aggregates, compared to rice control. Overall, LAG showed potential to control starch digestion kinetics of white rice with a mechanism that may involve formation of a protective layer on the rice grains (um) that reduces bolus break down (cm) and enzymatic hydrolysis (nm). Outcomes of this work will be used to identify conditions for further relevant in-vitro and in-vivo investigations.

Anti-diabetic and anti-cancer related health food properties of selected Sri Lankan traditional rice based porridges

Four Sri Lankan porridges including madathawalu (MWP), kaluheenati (KHP), mixed rice of sudu heenati, goda heenati, masuran, and dikwee (MXP) and special traditional porridge (STP) were screened for in vitro glycemic indices (GI), α-amylase inhibition and anti-glycation activities. All four porridges had the medium GI values, those were in the range of 40.5 ± 4 to 63.9 ± 2. The highest antiglycation activity was reported for MWP demonstrating IC50 of 228.20 ± 4.20 µg/mL. In relation to the α-amylase inhibition activity, the porridge extracts of MWP and STP low IC50 values (117.54 ± 1.92 µg/mL and 128.75 ± 5.91 µg/mL) showed their high capability to inhibit α-amylase enzyme. Due to the medium to low GI values and high antiglycation and α-amylase inhibition activities, traditional rice based porridges can be considered as effective for the prevention of diabetic conditions as well as from various complications in diabetic patients. Anticancer activity against human lung and HeLa cell lines revealed that KHP and MXP exhibited anticancer activity (IC50 of 274.6 μg/mL and 940.2 μg/mL respectively) against HeLa- human cervical cancer cells. In conclusion, porridge composites prepared using Sri Lankan traditional rice helped to eliminate or notably reduce nutrient deficiencies, and it provided numerous health benefits and economical gains.

Effect of instant jasmine rice coating combining Spirulina with edible polymers on physicochemical properties, textural properties and sensory acceptance

Coating is an effective and economic strategy to increase the functional property of food products. This study investigated the technical feasibility of adding Spirulina platensis to edible polymers, namely carboxymethyl cellulose (CMC) and maltodextrin (MD), in the coating of instant jasmine rice, using a central composite design (CCD). A total of 10 edible coating formulations comprising CMC (10-30% w/v) and MD (1-5% w/v) were evaluated to optimize the most suitable combination of physicochemical properties, textural attributes, and sensory acceptance. The resulting rice fortified with S. platensis and hydrocolloids showed improved textural and functional properties favourable for consumer acceptance. Among these, the optimum (20.0% MD, 1.0% CMC, and 2.0% S. platensis powder) increased the physicochemical properties and decreased textural properties compared with those of uncoated rice. This condition showed phycocyanin content of 1.4 mg/g, chlorophyll a of 181.5 µg/g, total phenolic compound (TPC) of 137.3 µg gallic acid equivalent (GAE)/g, and ferric reducing antioxidant power (FRAP) of 3.8 mg ferrous (Fe2+)/g with overall acceptability of 7.1 (like moderately). It can be stated that masking the colour and flavour of Spirulina with an edible coating could be a healthy alternative to commercial rice and used to fortify cereal products with algae.

Nutritional, Functional and Sensory Properties of Ready-To-Eat Chia and Quinoa Mix Enriched Low Amylose Rice Based Porridge Mixes

Ready-to-eat porridges are prepared from cereal flours. Pregelatinization of the starch component results in high hygroscopicity of porridge flours resulting in easy reconstitution. Chia and quinoa seeds are popular due to their health-promoting nutritional composition and functionality. In this study, 10%, 15 % and 20% of a pregelatinized low amylose ready-to-eat rice flour were substituted with a 1:1 mixture of chia and quinoa seed flours. Analysis of the significant difference between all the results was carried out by Duncan’s multiple range test at a significance level of 0.05. Substitution significantly enhanced levels of proteins, dietary fibres, iron, calcium, potassium, sodium and zinc. Palmitic, stearic and oleic acids were proportionately higher than lesser significant changes in linoleic and alpha-linolenic acid. Although thermal destruction caused a marked reduction of total phenolic and flavonoid contents, the relative rise in ferric and cupric ion reducing the antioxidant potentials suggested the probable formation of Maillard compounds with radical scavenging properties. Chia seed mucilage was found to play a critical role in thickness and viscosity development in the optimally reconstituted porridges. Supporting results were also obtained from the texture analysis of the porridges. However, the mucilage was observed to be sensitive to high cooking temperature resulting in lower cold paste viscosity in the rapid viscosity analysis study. The roasted aroma in porridges was more acknowledged. Substitution level of 20% gave an overall sensory score below the set acceptance level. Hence, porridge mixes prepared from the rice flour substituted up to 15% with the flour mix was sensorily acceptable, rich in macro and micronutrients and can serve as a therapeutic diet for infants, old-aged and patients with poor digestive systems.

Optimization of Processing Condition of Instant Rice to Lower the Glycemic Index

White rice is classified as having a low to high glycemic index (GI) depending on its amylose:amylopectin ratio. High GI food can be detrimental to diabetics since they can rapidly increase the glucose level in blood during digestion. Instant rice is increasing in popularity and is produced by dehydrating whole grain cooked rice, therefore, to make it more suitable for diabetics, the effect of the processes involved in the production on GI were tested. The objective was to optimize cooking temperature and the ratio of water to rice to reduce in vitro starch digestibility and GI of instant rice made from three Thai rice cultivars (Hom Mali (KDML105), Pathumthani Fragrant (PT) and Sao Hai (SH)) that had different amylose contents. Response surface methodology (RSM) was used to optimize the cooking conditions. The rapidly digestible starch (RDS) content and estimated glycemic index (eGI) decreased as cooking temperature decreased and the ratio of water to rice increased. The decrease in RDS content was associated with the increase in both slowly digestible starch (SDS) and resistant starch (RS) contents. The microstructure of instant rice kernels after cooking at higher temperature or lower volumes of water showed larger voids and a less compact surface, which facilitated enzymatic accessibility and increased starch digestibility. Rice cooked at higher temperature (90 °C) showed lower peak viscosity and breakdown in pasting properties, compared with lower temperature 82 °C. The optimal cooking condition for producing lower GI instant rice was cooking at 82 °C with 1.9-fold water volume. PRACTICAL APPLICATION: Rice has a high glycemic index (GI) that makes it unsuitable for consumption by many people with type 2 diabetes and obesity. Therefore, preparation of an instant rice product with a lower GI would ensure the product was beneficial to a wider range of the population.

Physicochemical and Thermal Properties of Extruded Instant Functional Rice Porridge Powder as Affected by the Addition of Soybean or Mung Bean

Legumes contain protein, micronutrients, and bioactive compounds, which provide various health benefits. In this study, soybean or mung bean was mixed in rice flour to produce by extrusion instant functional legume-rice porridge powder. The effects of the type and percentage (10%, 20%, or 30%, w/w) of legumes on the expansion ratio of the extrudates were first evaluated. Amino acid composition, color, and selected physicochemical (bulk density, water absorption index, and water solubility index), thermal (onset temperature, peak temperature, and transition enthalpy), and pasting (peak viscosity, trough viscosity, and final viscosity) properties of the powder were determined. The crystalline structure and formation of amylose-lipid complexes and the total phenolics content (TPC) and antioxidant activity of the powder were also measured. Soybean-blended porridge powder exhibited higher TPC, 2,2-diphenyl-1-picrylhydrazyl radical scavenging capacity, ferric reducing antioxidant power, amino acid, and fat contents than the mung bean-blended porridge powder. Incorporating either legume affected the product properties by decreasing the lightness and bulk density, while increasing the greenness and yellowness and the peak temperature and transition enthalpy. Expansion capacity of the extrudates increased with percentage of mung bean in the mixture but decreased as the percentage of soybean increased. Amylose-lipid complexes formation was confirmed by X-ray diffraction analysis results. Addition of soybean or mung bean resulted in significant pasting property changes of the porridge powder.

Optimization of instant dalia dessert pre-mix production by using response surface methodology

Dalia, a wheat-based, particulate containing dairy dessert is popularly consumed as a breakfast food and is also considered as a health food. Though popular throughout Northern parts of the country, its limited shelf-life even under refrigeration imposes severe restrictions on its organized manufacture and marketing. In order to promote dalia dessert as a marketable product, in the present study, a process was developed for manufacture of instant dalia pre-mix, as a dry product with long shelf-life, which could be attractively packaged and easily reconstituted for consumption. During the investigation, the effect of different levels of milk solids and wheat solids was studied on dalia pre-mix quality by employing a central composite rotatable design (CCRD). The suggested formulation had 17.82 % milk solids and 2.87 % wheat solids. This formulation was found to be most appropriate for manufacture of instant dalia pre-mix with predicted sensory scores (Max. 100) of 85.35, 41.98 and 67.27 for mouthfeel, consistency and flavor, respectively; the viscosity of the product was 941.0 cp.

Determination of Melatonin in Rice (Oryza sativa) Grains by Pressurized Liquid Extraction

Melatonin provides a number of benefits for human health. The study reported here concerns the optimization, validation, and application of analytical pressurized liquid extraction and high-performance liquid chromatography coupled to a fluorescence detector for the determination of melatonin in rice grains. The factors that are most likely to affect the extraction efficiency were optimized with a 2_IV^7-2 fractional factorial design. The optimum extraction conditions were achieved by applying 70% EtOAc in MeOH at 200 °C and 200 atm for a static time of 5 min in two cycles with 50% flushing and a 60 s purge to extract a 2.5 g rice sample. The method validation ensured excellent linearity, limit of detection, limit of quantification, precision, and recovery. Furthermore, the method was applied to various rice products composed of polished, whole grain, aromatic, black, black glutinous, red, and parboiled rice. All kinds of pigmented rice grains showed high levels of melatonin (>100 μg kg ^-1), and the highest levels were found in red rice.

Effects of Sucrose Stearate Addition on the Quality Improvement of Ready-To-Eat Samgyetang During Storage at 25℃

The effects of sucrose stearate at various concentrations (0.1%, 0.2%, and 0.3%, w/v) on the physico-chemical characteristics of ready-to-eat (RTE) Samgyetang were investigated during storage at 25℃ for 12 mon. Over the storage duration, the addition of sucrose stearate had no significant effects on the proximate composition of Samgyetang, including meat, broth, and porridge, or the hardness and spreadability of the porridge, although it resulted in significantly higher CIE L* values for the porridge. The CIE L* values of Samgyetang porridge with added sucrose stearate increased until 9 mon, while the control decreased until 6 mon, and the values for both changed insignificantly thereafter. The breast meat of Samgyetang treated with sucrose stearate showed higher percentages of polyunsaturated fatty acid after 3 mon and lower percentages of monounsaturated fatty acid after 6 mon compared to the control (p<0.05), while no significant differences were observed with the different sucrose stearate concentrations (p>0.05). The overall sensory acceptability scores were higher at sucrose stearate concentrations of 0.2% or 0.3% after 6 mon and at 0.1% after 9 mon compared to those of the control.

In vitro digestibility and physicochemical properties of milled rice

Rice is a staple diet as well as a major ingredient in many processed foods. The physicochemical and supra-molecular structure of eight rice varieties with amylose content from 9% to 19% were studied to elucidate the factors responsible for variation in enzymatic digestibility of raw and cooked rice. Parboiled rice had a digestion rate coefficient almost 4.5 times higher than the least digestible Low GI rice. The rate coefficient was found to be independent of helical structure and long range molecular order, possibly attributed to the effect of rice flour architecture. Strong swelling and pasting behaviour and lower gelatinisation temperature were linked with apparently higher in vitro digestibility but the relationship was statistically insignificant. It is concluded that the enzymatic susceptibility of rice flours are independent of supra-molecular structure and are most likely controlled by external factors not limited to particle size, presence of intact cell wall and other non-starch polymers.