Impact of physicochemical properties on duration and head rice yield during abrasive and friction milling of rice.

The physicochemical properties of four rice varieties representing high amylose (Jyothi and IR64), intermediate amylose (Taraori Basmati) and waxy (Agonibora) were evaluated to understand their influence on milling. Based on the grain dimensions, Jyothi and Agonibora were classified as long and medium, IR64 as long and slender, and Basmati as extra-long and slender. The head rice yield (HRY) was higher with abrasive milling (61-75%) compared to friction milling (10-60%) although it required longer milling duration. Lower grain thickness, hardness and, amylose and higher bran fat content reduced the friction milling duration while these properties prolonged the duration in abrasive milling. Agonibora variety with low amylose content and high-fat content exhibited the highest HRY in both the types of milling. The study revealed that the selection of milling process should be made with due importance to grain geometry as well as its chemical properties.

Influence of milling on the nutritional composition of bran from different rice varieties.

The nutritional composition of bran from four rice varieties namely, Jyothi/IR64, Basmati and Agonibora representing high amylose, intermediate amylose and waxy, respectively were evaluated with friction and abrasive mills at different degrees of milling (DOM). Fat and protein content of the bran inversely correlated to amylose content of rice variety. The fat and fibre contents reduced with increased DOM due to increasing starch influx from the endosperm. Abrasive milling produced bran with higher protein content and total dietary fibre, resulting in superior quality bran, while friction milling led to higher fat. Agonibora bran was found to be superior in terms of nutritional quality. Industrial milling resulted in higher protein content in bran, and Jyothi variety had a better amino acid profile.

Status in physical properties of coloured rice varieties before and after inducing retro-gradation.

Three varieties of paddy in brown, red (non-waxy) and black (waxy) forms were de-husked and milled before and after inducing retro-gradation and their physical properties were studied. Normalized grain weight, porosity of parboiled paddy (PP) and its de-husked rice (DR), were high compared to their respective native. True and bulk density were lowest for black variety, its DR, its raw and parboiled forms compared to other varieties of paddy. Angle of repose increased from raw paddy to PP whereas it decreased from raw DR to parboiled DR. Under similar conditions of milling of DR, raw and parboiled milled rice of black variety was the darkest. Raw husk showed higher EMC compared to husk of parboiled. Hardness followed the pattern: Raw: Paddy (~230-280 N) > DR (~120-260 N) > Milled rice (~110 N); for parboiled: DR (~270-480 N) > PP (~260-425 N) > Parboiled milled rice (~250-340 N). Cooking time was high for DR of parboiled ones and least for waxy raw milled rice. Results of this study will be helpful in understanding the quality of pigmented rice cultivars, design and fabrication of some of the equipments in rice processing industry.

Formulation and nutritional evaluation of multigrain ready-to-eat snack mix from minor cereals.

A ready-to-eat nutritious snack mix was developed by blending the flour from popped millets and legumes with sugar and other ingredients in the optimized proportion of 30:20:27:23. The nutrient composition, functional properties, sensory qualities and storage characteristics of the product were analysed. The product contained protein 14.0 ± 0.07 g, fat 14.5 ± 0.72 g, carbohydrates 59.0 ± 1.20 g and dietary fiber 6.3 ± 0.04 g per 100 g of mix. The sensory evaluation of the product revealed that color, taste, texture, aroma, appearance and overall quality were in acceptable range with mean score of 6.8. Shelf life of the product was about 90 days under normal conditions when stored in low density polypropylene pouches. The work indicates the potential of using coarse cereals and legumes for preparation of nutritious food for societal program.

Shelf stable multigrain halwa mixes: preparation of halwa, their textural and sensory studies.

Multigrain halwa mixes (four types) were prepared from cereals, millets, legumes, nuts and condiments. These mixes had around 4% initial moisture content (IMC), during storage studies they had 23 to 32% as equilibrium relative humidity (ERH); 5 to 8% as the critical moisture content (CMC) and critical relative humidity (CRH) for these mixes were ~ 60%. Packaging material for storing these mixes was 75 µm thickness LDPE pouches. Under accelerated storage, these mixes picked up moisture up to 9% and at ambient up to 6.4%. Free fatty acids ~18% was developed under accelerated condition for 90 days; under ambient condition ~14% for 180 days. Ragi based spicy halwa mix could develop FFA up to 120%, which was due to the presence of tricarboxylic acid as one of the ingredient in this particular mix. Halwa mixes can be stored for 75 days under accelerated and 180 days under ambient conditions. Halwa prepared from these mixes had 26 to 31% moisture; protein, fat, carbohydrates and ash content were 5.7 to 6.3%, 7.9 to 8.7%, 54 to 58%, 1.6 to 3.3%, respectively. Energy derived from these ranged from 1,318 to 1,380 kJ/100 g. Ragi based spicy multigrain halwa was harder and chewy in texture; while wheat based multigrain halwa was softer. Dark brown colour persisted for Ragi based spicy multi grain halwa because of the inherent colour of the finger millet, ghee aroma and sweetness was insignificant for all the 4 types of halwa.

Preparation, nutritional composition, functional properties and antioxidant activities of multigrain composite mixes.

Multigrain composite mixes were prepared from different cereals, legumes, millets, nuts along with condiments by different processes. Multigrain composite mixes had 10 to 12% moisture, 56 to 61% carbohydrate, 15 to 20% protein, 9 to 13% crude lipid and 2 to 3% ash. Energy value ranged from ~1600 to 1700 kJ/100 g. Among the vitamins studied, thiamine and riboflavin content varied from 0. 23 to 0.45 mg% and from 8.7 to 21.6 microgram% respectively. Dietary fibre was in the range of 12.4-16.5%. Swelling power of these mixes was about 10; however solubility varied from 17 to 22%. In-vitro Starch digestibility varied from 60 to 76%. Phytic acid content in these multigrain composite mixes varied from 0.6 to 0.8%. Poly-phenols ranged from 1.2 to 1.5%, DPPH free radical scavenging activity ranged from 75.2-86.2% and metal chelating activity ranged from 1.9 to 3.9%. Pasting profile by a Brabender Viscograph of these mixes indicated that they have cross linked starch type behaviour. These multigrain composite mixes can be used for the preparation of food formulations, savory products, pan cake, snacks preparation like muruku and chakli.

Effect of processing paddy on digestibility of rice starch by in vitro studies.

Paddy (Oryza sativa L) (variety 'IR - 64'), was parboiled, puffed by sand roasting and flaked by edge runner and roller flaker and variations in physical and physicochemical properties were studied. Moisture contents were lower (5.8-10.8%) in processed rice products compared to raw materials (11.8%). Ratio of rice to sand in the case of puffed rice preparation was optimized. The equilibrium moisture content was 27.4% in raw rice while it was much higher (38.9-81.0%) in processed rice. Sedimentation volume was lowest (6.2 ml) in raw rice and highest (18.8 ml) in popped rice. Starch content was 84.8 and 76.5-83% in raw and processed rice, respectively. In vitro starch digestibility was highest in roller flaker flakes and lowest in raw milled rice. Among the ready to eat products, popped rice showed least starch digestibility (∼30%).

A comparative study on starch digestibility, glycemic index and resistant starch of pigmented ('Njavara' and 'Jyothi') and a non-pigmented ('IR 64') rice varieties.

In vitro starch digestibility and glycemic indices of three rice varieties- 'Njavara', 'Jyothi' (pigmented rice verities) and 'IR 64' (non-pigmented rice) with similar amylose content were studied. Starch digestibility studies showed differences in glycemic response in three types of rice. The rate of starch hydrolysis was maximum (67.3%) in 'Njavara' rice compared to other two rice varieties. 'Njavara' exhibited the lowest kinetic constant (k) indicating inherent resistance to enzymatic hydrolysis. The glycemic load (GL) and glycemic index (GI) of 'Njavara' were similar to 'Jyothi' and 'IR 64'. Resistant starch content was high in pigmented rice varieties compared to 'IR 64'. The resistant starch content of dehusked and cooked rice increased with the storage time at refrigeration temperature (4°C). 'Njavara' is an easily digestible rice and can be used for baby and geriatric foods.

Influence of parboiling of red paddy varieties by simple hot soaking on physical, nutrient, phytochemical, antioxidant properties of their dehusked rice and their mineral, starch, and antioxidant's bioaccessibility studies.

The objective of this study was to know about the effect of simple parboiling on physical properties, proximate composition, phenolic compounds, and antioxidant activity.  These were  studied in raw and parboiled paddy varieties as well as bioaccessibility of specific nutrients (minerals, starch, and antioxidants). The pigmented rice paddy varieties such as Jyothi, Meter & Athikaraya were parboiled by hot soaking treatment after soaking for 2, 2½, and 3 hr. Athikaraya rice showed high protein, low ash in raw and parboiled than other varieties. Amylose equivalents of all three varieties exhibited in the range of 24%-27% (d.b). Whereas, the soluble amylose content showed 12.7, 8.7, and 7.7% (d.b) in Athikaraya, Meter and Jyothi rice varieties, respectively. Jyothi rice showed less cooking time and more cooking volume. Athikaraya showed high phenolic content and antioxidant properties compared to other two varieties. The dialysability of minerals, starch, and antioxidants were increased due to simple hot soaking parboiling. PRACTICAL APPLICATIONS: The present study has the significance in assessing the variation among different pigmented rice varieties after parboiling by simple hot soaking with various soaking periods. The industrial advantage of this method is, there is no usage of boiler for cooking the paddy by steam, which was economically better. The information gained by this study might be beneficial for consumers and suppliers regarding the quality of the selected pigmented rice varieties with respect to nutrient composition, antioxidant activities, and bioaccessibility of minerals, starch, and antioxidants. Ultimately, the present study can lead to better appreciation of pigmented rice and assist food processors in selecting rice variety with unique characteristics for specialty food preparations.

Bioactives-retained non-glutinous noodles from nixtamalized Dent and Flint maize.

Nixtamalization is a well-known pre-treatment technique in the tortilla industry. Nixtamalized maize (nixtamal) is known for its modified physicochemical as well as nutritional attributes. In the present study, two types of nixtamalization processes (traditional and ecological) were employed for the development of whole-grain-maize-based noodles using Dent and Flint maize genotypes. Results showed that ecological nixtamalization had resulted in better cooking and textural qualities of noodles compared to the one prepared traditionally. Dent maize noodles from traditional and ecological nixtamalization had lower retention of phenolics (40 and 64%, respectively) whereas, Flint maize noodles retained 50 and 66% phenolics, respectively. Dent maize noodles had undergone phenolics loss of 5-6% on cooking while those of Flint maize lost only 2%. Ecological nixtamalization maintained the pH of the cooking liquor within an acidic-neutral range and yielded noodle with higher retention of phenolics whereas, the traditional process negatively affected the antioxidant compounds and their properties.

Antioxidative free and bound phenolic constituents in botanical fractions of Indian specialty maize (Zea mays L.) genotypes.

Specialty maize genotypes viz. QPM (quality protein maize), Baby corn, Popcorn and Sweet corn, which are usually consumed in whole forms can be good supplements of phenolic antioxidants. Botanical fractions of these maize genotypes were analyzed to explore the distribution of free and bound phenolics. HPLC and ESI-MS/MS results indicated the presence of vanillic, syringic, p-hydroxybenzoic, caffeic, p-coumaric, ferulic and isoferulic acids along with cyanidin-3-O-glucoside, kaempferol and quercetin. Germs of maize samples contained significantly higher free phenolics than pericarps, whereas, pericarps contained 74-83% of bound ones. QPM and Popcorn contained only 3% free phenolics whereas, Baby corn and Sweet corn had 14-17%. Unlike in peroxide scavenging and reducing capacity, anti-radical capacity of free phenolics of germs was significantly higher than that of pericarps. Free phenolics contributed 0.2-1.65%, 2-5% and 42-49% in anti-radical, peroxide scavenging and reducing capacity, respectively. Among lipophilic tocochromanols γ-tocopherol was the most abundant isomer in the samples among which Sweet corn contained the most (84.2 µg/g). Data showed that specialty maize genotypes are rich sources of hydrophilic and lipophilic bioactives and are natural antioxidants.

Physical, physicochemical and nutritional characteristics of Bhoja chaul, a traditional ready-to-eat dry heat parboiled rice product processed by an improvised soaking technique.

Bhoja chaul is a traditional whole rice product processed by the dry heat parboiling technique of low amylose/waxy paddy that is eaten after soaking in water and requires no cooking. The essential steps in Bhoja chaul making are soaking paddy in water, roasting with sand, drying and milling. In this study, the product was prepared from a low amylose variety and a waxy rice variety by an improvised laboratory scale technique. Bhoja chaul prepared in the laboratory by this technique was studied for physical, physicochemical, and textural properties. Improvised method shortened the processing time and gave a product with good textural characteristics. Shape of the rice kernels became bolder on processing. RVA studies and DSC endotherms suggested molecular damage and amylose-lipid complex formation by the linear B-chains of amylopectin, respectively. X-ray diffractography indicated formation of partial B-type pattern. Shifting of the crystalline region of the XRD curve towards lower values of Bragg's angle was attributed to the overall increase in inter-planar spacing of the crystalline lamellae. Resistant starch was negligible. Bhoja chaul may be useful for children and people with poor state of digestibility.

Production of okara and soy protein concentrates using membrane technology.

Microfiltration (MF) membranes with pore sizes of 200 and 450 nm and ultrafiltration (UF) membranes with molecular weight cut off of 50, 100, and 500 kDa were assessed for their ability to eliminate nonprotein substances from okara protein extract in a laboratory cross-flow membrane system. Both MF and UF improved the protein content of okara extract to a similar extent from approximately 68% to approximately 81% owing to the presence of protein in the feed leading to the formation of dynamic layer controlling the performance rather than the actual pore size of membranes. Although normalized flux in MF-450 (117 LMH/MPa) was close to UF-500 (118 LMH/MPa), the latter was selected based on higher average flux (47 LMH) offering the advantage of reduced processing time. Membrane processing of soy extract improved the protein content from 62% to 85% much closer to the target value. However, the final protein content in okara (approximately 80%) did not reach the target value (90%) owing to the greater presence of soluble fibers that were retained by the membrane. Solubility curve of membrane okara protein concentrate (MOPC) showed lower solubility than soy protein concentrate and a commercial isolate in the entire pH range. However, water absorption and fat-binding capacities of MOPC were either superior or comparable while emulsifying properties were in accordance with its solubility. The results of this study showed that okara protein concentrate (80%) could be produced using membrane technology without loss of any true proteins, thus offering value addition to okara, hitherto underutilized. Practical Application: Okara, a byproduct obtained during processing soybean for soymilk, is either underutilized or unutilized in spite of the fact that its protein quality is as good as that of soy milk and tofu. Membrane-processed protein products have been shown to possess superior functional properties compared to conventionally produced protein products. However, the potential of membrane technology has not been exploited for the recovery of okara protein. Our study showed that protein content of okara extract could be improved from approximately 68% to approximately 81% without losing any true proteins in the process.

Physicochemical and genetic analysis of an endemic rice variety, Njavara (Oryza sativa L.), in comparison to two popular South Indian cultivars, Jyothi (PTB 39) and IR 64.

Njavara is a medicinal rice strain, endemic to Kerala, South India, bestowed with medicinal qualities. Genetic variations and some of the physicochemical properties were studied using standard molecular protocols and compared with those of nonmedicinal rice varieties: Jyothi and IR 64. Njavara showed 11 unique positive and 36 unique negative markers to differentiate it from Jyothi and IR 64. Genetic similarity coefficient studies showed two well-defined clusters separating Njavara from Jyothi and IR 64. All the three varieties had waxy gene Wx(a) allele. Njavara had (CT)(n) repeats at (CT)(10), while Jyothi and IR 64 had repeats at (CT)(11) in the 5'-untranslated region of waxy gene. Njavara showed a CGTG sequence, while Jyothi and IR 64 had a CGCG sequence at the 14th exon of Sbe 1 gene. Njavara, Jyothi, and IR 64 have similar amylose equivalent (AE), which was confirmed by microsatellite markers. The SSR primers for protein content and setback viscosity primer (RM 4608) were observed to be polymorphic in case of Njavara. Njavara rice, with a distinct gene pool and medicinal properties, can be exploited as a nutraceutical rice.