Antioxidant,anti-amylase and anti-glycation potential of brans of some Sri Lankan traditional and improved rice (Oryza sativa L.) varieties

Brans of 23 traditional and 12 improved (both red and white) rice varieties in Sri Lanka were screened for anti-amylase and anti-glycation activities in vitro. Varieties which showed the highest inhibitory activities at screening were further investigated for anti-glucosidase and glycation reversing as anti-diabetic properties. The same varieties were studied for selected antioxidant properties. Significantly high anti-amylase and anti-glycation activities were observed for bran extracts of red varieties compared to white varieties at screening. Traditional red rice varieties, Masuran, Sudu Heeneti, Dik Wee and Goda Heeneti, exhibited significant and dose dependent anti-amylase, anti-glycation and glycation reversing activities. These varieties also showed marked antioxidant properties. It is concluded that brans of Sri Lankan traditional red rice varieties Masuran, Sudu Heeneti, Dik Wee and Goda Heeneti may be potential food supplements for diabetes.     

Phenolic compounds,antioxidant capacity and gelling properties of glucoarabinoxylans from three types of sorghum brans

Arabinose to xylose ratio (A/X), phenolics, antioxidant capacity and gelling properties were evaluated in glucoarabinoxylans (GAX) extracted from white (W-GAX), red (R-GAX) and high tannin (T-GAX) sorghum brans (SB). The characterization of arabinoxylans from corn fiber (CFAX) was used as benchmark. Sorghum GAX had higher branched structure (A/X 1.08–1.41) than CFAX (0.59). Nine 3-deoxyanthocyanins (3-DAs) were identified in SB and two glycosylated forms remained associated to the R-GAX and T-GAX extracts. T-GAX was the only that contained tannins (0.41 mg catechin equivalents (CE)/g dry basis (db)) and exerted the highest antioxidant capacity (81.75 mM Trolox equivalents (TE)/g db) followed by R-GAX (48.49 mM TE/g db), which contained the highest amount of 3-DAs (0.11 mg Luteolinidin equivalents (Lut eq)/g db), and W-GAX (35.45 mM TE/g db) that was not significantly different from the CFAX (25.83 mM TE/g db). Among sorghums, only the W-GAX gelled but it formed a weaker gel compared to CFAX likely due to its lower hydroxycinnamic acids (HCA) concentration. The presence of 3-DAs in the structure of R-GAX and T-GAX affected negatively their solubility and gelling properties. The different SB showed potential as sources of GAX with antioxidant capacity.     

Characterisation of starch during germination and seedling development of a rice mutant with a high content of resistant starch

To acquire a better understanding of whether RS influences the dynamics of in vivo starch digestion and seed vigour, the high-RS rice mutant RS4 (RS ca. 10%) and the wild type R7954 were used to investigate total amylase activity, seedling vigour, starch content and starch granule structure during germination. RS4 exhibited similar seed vigour to R7954. Amylose and amylopectin in R7954 showed synchronous degradation throughout the whole process, while amylopectin was hydrolysed significantly faster than amylose in RS4 during the earlier germination stages. The starch residues of RS4 after germination (GD) lost endotherm peaks and showed a special X-ray diffraction pattern with only two peaks at around 16.90° and 21.62°, probably due to remnants of amylopectin and its tight crosslinking with the cell wall. The remaining starch after 10 GD, primarily amylopectin may make a critical contribution to total resistant starch content. These results indicated that RS had no negative impact on seed vigour in rice lines, although RS cannot be hydrolysed by α-amylase from human and animal in vitro. By appropriately increasing the special amylopectin fraction, a new breeding programme of high RS crops and improvement in the eating quality of high RS rice varieties might be achieved.     

Quinoa (Chenopodium quinoa Willd.) protein hydrolysates with in vitro dipeptidyl peptidase IV (DPP-IV) inhibitory and antioxidant properties

The potential of quinoa to act as a source of dipeptidyl peptidase IV (DPP-IV) inhibitory and antioxidant peptides was studied. A quinoa protein isolate (QPI) with a purity of 40.73 ± 0.90% was prepared. The QPI was hydrolysed at 50 °C for 3 h with two enzyme preparations: papain (P) and a microbial papain-like enzyme (PL) to yield quinoa protein hydrolysates (QPHs). The hydrolysates were evaluated for their DPP-IV inhibitory and oxygen radical absorbance capacity (ORAC) activities. Protein hydrolysis was observed in the QPI control, possibly due to the activity of quinoa endogenous proteinases. The QPI control had significantly higher DPP-IV half maximal inhibitory concentrations (IC₅₀) and lower ORAC values than QPH-P and QPH-PL (P < 0.05). Both QPH-P and QPH-PL had similar DPP-IV IC₅₀ and ORAC values. QPH-P had a DPP-IV IC₅₀ value of 0.88 ± 0.05 mg mL⁻¹ and an ORAC activity of 501.60 ± 77.34 μmol Trolox equivalent (T.E.) g⁻¹. To our understanding, this is the first study demonstrating the in vitro DPP-IV inhibitory properties of quinoa protein hydrolysates. QPHs may have potential as functional ingredients with serum glucose lowering properties.     

Effect of hydrostatic high pressure pretreatment on flavor volatile profile of cooked rice

The impact of high hydrostatic-pressure (HHP) processing on the volatile profile of cooked Japonica rice (Wuchang) and Jasmine rice (Complete Wheel) was investigated by SPME–GC/MS. Presoaked samples were treated at 200, 400 and 600 MPa for 10 min and then cooked for volatile compound analysis. Seventy-seven compounds were identified in two cooked rice varieties: 20 aldehydes, 16 alcohols, 14 ketones, 9 arenes, 7 esters, 5 alkanes, 3 olefins and 3 hetero-cycle compounds. Results showed that both pressure level (P < 0.01) and rice variety (0.01 < P < 0.05) significantly impact the volatile compounds in rice and there is also an interaction between pressure and rice variety (P < 0.01). Overall, HPP decreased the amount of aldehydes more obviously in Complete Wheel rice than that in Wuchang variety. Both 200 and 400 MPa increased the levels of alcohols, ketones, esters and olefins, but reduced those of heterocycles, alkanes and arenes. Similar volatile change trends were found at 600 MPa except the concentration of each component was closer to that of control group. Based on the changes in the three key flavor compounds in rice (aldehydes, alcohols and ketones), the HPP process could be a suitable alternative to traditional pretreatment for improving flavor in cooked rice.     

Formulating low glycaemic index rice flour to be used as a functional ingredient

Amylose and resistant starch (RS) content in rice flour were manipulated. The experiment was conducted using a full factorial design. Rice flour with average amylose content of 20 and RS content of 0.5 g/100 g dry sample was fortified with pure amylose from potato and high RS modified starch to reach the final amylose content of 30, 40 and 50 and RS content of 2, 4 and 6 g/100 g dry sample. The fortified rice flours were examined for their gelatinisation properties, in-vitro enzymatic starch digestion and gel textural properties. It was found that amylose and RS significantly affect all the fortified rice flour properties (p < 0.05). High amylose and RS improved starch digestion properties, reducing the rate of starch digestion and lowering the glycaemic index (GI) values. Amylose had a more pronounced effect on the fortified rice starch properties than RS. In this study, the fortified rice flour which contained amylose and RS of approximately 74 and 9 g/100 g dry sample respectively was used to produce rice noodles. The noodles exhibited low GI values (GI < 55). However, amylose and RS affected the textures of rice noodles providing low tensile strength and break distance (extensibility).     

Variation in gluten quality parameters of spring wheat varieties of different origin grown in contrasting environments

The aim of this study was to investigate variation in protein content and gluten viscoelastic properties in wheat genotypes grown in two mega-environments of contrasting climates: the southeast of Norway and Minnesota, USA. Twelve spring wheat varieties, nine from Norway and three HRS from Minnesota, were grown in field experiments at different locations in Norway and Minnesota during 2009–2011. The results showed higher protein content but lower TW and TKW when plants were grown in Minnesota, while the gluten quality measured as Rmax showed large variation between locations in both mega-environments. On average, Rmax of the samples grown in Minnesota was higher than those grown in Norway, but some locations in Norway had similar Rmax values to locations in Minnesota. The data showed inconsistent relationship between the temperature during grain filling and Rmax. Our results suggest that the weakening effect of low temperatures on gluten reported in this study are caused by other environmental factors that relate to low temperatures. The variety Berserk showed higher stability in Rmax as it obtained higher values in the environments in Norway that gave very weak gluten for other varieties.     

Improved functional properties of pasta: Enrichment with amaranth seed flour and dried amaranth leaves

The present investigation evaluated the effects of dried amaranth leaves (DAL) and amaranth seed flour (AF) as ingredients for pasta production and their contribution to antioxidant activity. Cooking quality, proximal and aroma analysis, antioxidant capacity and sensory evaluations were performed. The results demonstrated that pastas with amaranth ingredients had decreased cooking time, increased cooking loss percentage, and decreased luminosity values compared with semolina control pasta. Pastas with both AF and DAL demonstrated the highest protein, crude fiber and ash contents. The addition of DAL resulted in higher contents of iron, zinc, magnesium and potassium compared with the control pasta. TC, FRAP and ORAC assays showed that the pastas exhibited an important reduction in antioxidant capacity by cooking process. Formulas with DAL showed the higher antioxidant capacity values after cooking. The addition of AF and DAL has proved to increase the functional benefits of the pasta.     

Suitability of tef varieties in mixed wheat flour bread matrices: A physico-chemical and nutritional approach

Wheat flour replacement from 0 to 40% by single tef flours from three Ethiopian varieties DZ-01-99 (brown grain tef), DZ-Cr-37 (white grain tef) and DZ-Cr-387 (Quncho, white grain tef) yielded a technologically viable ciabatta type composite bread with acceptable sensory properties and enhanced nutritional value, as compared to 100% refined wheat flour. Incorporation of tef flour from 30% to 40% imparted discreet negative effects in terms of decreased loaf volume and crumb resilience, and increase of crumb hardness in brown tef blended breads. Increment of crumb hardness on aging was in general much lower in tef blended breads compared to wheat bread counterparts, revealing slower firming kinetics, especially for brown tef blended breads. Blended breads with 40% white tef exhibited similar extent and variable rate of retrogradation kinetics along storage, while brown tef-blended breads retrograded slower but in higher extent than control wheat flour breads. Breads that contains 40% tef grain flour were found to contain five folds (DZ-01-99, DZ-Cr-387) to 10 folds (DZ-Cr-37) Fe, three folds Mn, twice Cu, Zn and Mg, and 1.5 times Ca, K, and P contents as compared to the contents found in 100% refined wheat grain flour breads. In addition, suitable dietary trends for lower rapidly digestible starch and starch digestion rate index were met from tef grain flour fortified breads.     

Enhancement of biocontrol efficacy of Pichia membranaefaciens by hot water treatment in postharvest diseases of citrus fruit

Effects of hot water treatment (HWT; 53 °C for 2 min) and Pichia membranaefaciens, either alone or in combination, on controlling Penicillium italicum, Penicillium digitatum, and natural infection in citrus fruit were investigated. Results showed that the combined treatment significantly reduced disease incidence and lesion diameters of blue and green molds in artificially inoculated fruit whether the pathogens were inoculated after or before the treatment compared with the treatment of P. membranaefaciens or HWT alone. The combination of P. membranaefaciens with HWT was as effective as the fungicide treatment in natural infection trials. Application of HWT did not affect the growth of P. membranaefaciens in the wounds of citrus fruit at 20 °C or 4 °C. P. membranaefaciens combined with HWT effectively enhanced the phenylalanine ammonia-lyase, peroxidase, polyphenoloxidase, chitinase, and β-1,3-glucanase activities and stimulated the synthesis of phenolic compounds. These results suggest that the use of HWT is a useful approach to improve the efficacy of P. membranaefaciens in postharvest diseases of citrus fruit.     

Thermal degradation kinetics of bioactive compounds from black rice flour (Oryza sativa L.) extracts

The effect of thermal processing on the degradation of the phytochemicals in black rice flour by means of fluorescence spectroscopy and degradation kinetics was investigated. In order to investigate the influence of food matrices, a comparative analysis between integral rice flour and different fractions was performed. The preliminary compositional results suggested a higher content in phytochemicals in fraction four of the seven fractions of black rice flour, which was sifting through a sieve with a diameter of 180 μm. The compositional complexity was highlighted by fluorescence spectroscopy. The heat-treatment caused structural changes that led to red- or blue-shifts in maximum emission. The first-order kinetic model was used to describe the mechanism of degradation. The activation energies were 10.07 ± 1.04 kJ/mol for total polyphenolic, 7.26 ± 0.58 kJ/mol for total monomeric anthocyanins and 6.71 ± 1.12 kJ/mol for antioxidant activity in case of integral flour extract. For fraction four extract obtained by, the E_a values were: 3.51 ± 0.53 kJ/mol, 11.49 ± 1.47 kJ/mol, 15.80 ± 1.50 kJ/mol and 19.91 ± 3.27 kJ/mol, respectively. The calculated values of the activation energy revealed higher temperature dependence of total polyphenols in integral flour and of antioxidant activity in fraction four, respectively.     

Modeling the effects of microfluidization conditions on properties of corn bran

Corn bran was microfluidized through a 200-μm channel in the pressure range of 124.1–158.7 MPa for 1–5 passes following the central composite experimental design. Physicochemical properties and antioxidant properties of microfluidized bran samples were measured and fitted to the second order polynomial model. The response surface equations obtained showed that all the properties examined had a positive linear relationship with pressure and a negative quadratic relationship with number of passes except for ABTS radical scavenging activity which was quadratically related to both processing parameters. The number of passes generally had a more pronounced effect on the examined properties compared with pressure. Within the experimental range, the maximum values of swelling capacity, water-holding capacity, and oil-holding capacity were respectively 10.62 ml/g d.w. (at 158.7 MPa), 5.49 g water/g d.w. (at 158.7 MPa), and 4.61 g oil/g d.w. (at 124.1 MPa); the maximum values of surface reactive phenolic content, DPPH and ABTS radical scavenging activities were 148.80 mg/FAE g d.w. (at 158.7 MPa), 50.02 μmol TE/g d.w. (at 158.7 MPa), and 47.90 μmol TE/g d.w. (at 145.9 MPa), respectively. All maximum values of the properties occurred at 5 passes.     

Effect of high molecular weight glutenins and rye translocations on soft wheat flour cookie quality

The influence of high molecular weight glutenin subunits (HMW-GS) on wheat breadmaking quality has been extensively studied but the effect of different Glu-1 alleles on cookie quality is still poorly understood. This study was conducted to analyze the effect of HMW-GS composition and wheat-rye translocations on physicochemical flour properties and cookie quality of soft wheat flours. Alleles encoded at Glu-A1, Glu-B1 and Glu-D1 locus had a significant effect over physicochemical flour properties and solvent retention capacity (SRC) profile. The null allele for Glu-A1 locus presented the highest cookie factor observed (CF = 7.10), whereas 1BL/1RS and 1AL/1RS rye translocations had a negative influence on CF. The three cultivars that showed the highest CF (19, 44 and 47) had the following combination: Glu-A1 = null, Glu-B1 = 7 + 8, Glu-D1 = 2 + 12 and no secalins. Two prediction equations were developed to estimate soft wheat CF: one using the HMW-GS composition and the other using physicochemical flour parameters, where SRCsuc, SRC carb, water-soluble pentosans, damaged starch and protein turned out to be better CF predictors. This data suggests that grain protein allelic composition and physicochemical flour properties can be useful tools in breeding programs to select soft wheat of good cookie making quality.     

High pressure processing manipulated buckwheat antioxidant activity,anti-adipogenic properties and starch digestibility

Effect of high pressure processing (HPP) on buckwheat nutritional properties is investigated in this study. The results indicated that the digestion of buckwheat starches of untreated and HPP treated at room temperature (RT) showed an “internal corrosion” pattern. However, an “exocorrosion” digestion behavior was observed for the starches of HPP treated sample at 45 °C, which might be due to the formation of amylose–lipid complexes during the process as revealed by X-ray diffraction (XRD). HPP treatment at 45 °C increased the antioxidant activity of the buckwheat as measured using 1,1′-diphenyl-2-picrylhydrazylvalue (DPPH) and iron chelating capacity (ICC) compared to untreated sample (P < 0.05), which might be associated with the release of bound phenolic compounds. More importantly, this is the first study to investigate the ability of buckwheat extract for inhibiting the formation of fat droplets using a C3H10T1/2 mesenchymal stem cell line, and found that the extract of buckwheat after HPP treatment at 45 °C demonstrated significant anti-adipogenic effects. This study suggested the HPP treatment at an increased temperature (45 °C) achieved a better nutritional value of the buckwheat than both untreated and treated at RT.     

Effect of soaking temperature on commingled rice properties

Parboiling involves soaking, steaming, and drying, and soaking is important in achieving desired parboiled rice properties. This study investigated the effects of soaking temperature and commingling on rice properties prior to steaming. Rough rice of four cultivars (Taggart, CL151, XL753, and CL XL745) and their combinations at 1:1 wt ratio were soaked at 65, 70 or 75 °C for 3 h, and dried. Both soaking temperature and difference in onset gelatinization temperature (T_o) of individual cultivars in commingled rice affected milling and physicochemical properties. The head brown rice yield was greater when the soaking temperature was below but close to the T_o for individual rice cultivars, but became difficult to predict for commingled rice. Commingled rice consisting of high T_o rice cultivars required higher soaking temperatures to reduce chalkiness during soaking. The color attributes of commingled rice was predominately affected by the cultivar that exhibited the most change. The gelatinization properties were governed by the low-T_o cultivar, whereas the pasting properties were more influenced by the high-T_o cultivar for the commingled rice. Therefore, using commingled rice with a wide range of gelatinization temperature as a feedstock may lead to inconsistent quality of parboiled rice.     

Preparation of protein and mineral rich fraction from grain amaranth and evaluation of its functional characteristics

Grain amaranth was fractionated to prepare a seed coat rich fraction along with the fine seed coat, middling and flour fractions. The nutritional content of the coarse seed coat fraction and its antioxidant potential were evaluated. It was observed that, the coarse seed coat fraction contained highest protein (17.81 g/100 g), dietary fiber (25.78 g/100 g), free sugar (2.25 g/100 g), calcium (1115 mg/100 g), sodium (279 mg/100 g), magnesium (178.4 mg/100 g) and potassium (398.8 mg/100 g) contents compared to all other fractions. The carbohydrate and protein digestibility of all the fractions were more than 80%. A slight decrease in linoleic acid and a concurrent increase in palmitic acid contents were observed in coarse seed coat fraction. The total phytic acid increased and total polyphenols contents decreased in the coarse seed coat fraction compared to the native grain. The DPPH, ABTS and total antioxidant activities are comparatively high in this particular fraction. The study indicated a possibility of preparation of a protein, fiber and mineral rich fraction from grain amaranth with good antioxidant potential which can be used as a functional food ingredient.     

Effects of particle size on the quality attributes of reconstituted whole-wheat flour and tortillas made from it

The objective of this study was to examine the effects of whole-wheat flour (WWF) particle size on the quality attributes of WWF tortillas. WWF samples of different particle size distributions from commercial U.S. hard white (median diameters: 175.7, 128.6, 120.0, 108.5 and 102.4 μm), hard red winter (median diameters: 173.7, 133.6, 124.3, 110.8 and 104.2 μm) and hard red spring (median diameters: 173.7, 132.1, 124.7, 112.9, 106.3 μm) wheat classes were obtained by fine grinding of bran and shorts and re-combining with the rest of fractions. For all three wheat classes, as WWF median particle size decreased, the L* (lightness) value decreased but the adjusted damaged starch, polyphenol oxidase activity, and a* and b* values increased. Mixolab data showed that development time decreased as WWF particle size was reduced, while stability time and starch retrogradation increased. As for WWF tortilla quality, the breaking force and extensibility increased with decreasing particle size from ∼175 to 129–134 μm, but diameter and thickness were not significantly affected. The results indicated that reducing the median particle sizes of WWFs from ∼175 μm to ∼130 μm would significantly improve the WWF tortilla quality.     

Nutritional components and antioxidant properties of seven kinds of cereals fermented by the basidiomycete Agaricus blazei

The aim of this work was to evaluate the effects of solid-state fermentation (SSF) by basidiomycete Agaricus blazei Murrill (ABM) on the nutritional components and antioxidant properties of wheat, rice, oat, corn, millet, broomcorn millet and sorghum.The results showed that the contents of nutritional components in the fermented cereals varied with the fermentation time. After SSF of ABM, the enhancement rates of millet in total phenols, amino acid nitrogen and water-soluble protein content were the highest, which were respectively 4.03, 12.04 and 10.37 times higher than that of the control; the enhancement rates of wheat in total protein and reducing sugar content were the highest, which were 0.32 and 100.77 times higher than that of control. According to 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging capacity, reducing power, ferrous ion chelating ability and superoxide anion radical scavenging ability of ethanolic extracts from the fermented cereals, it was shown that the antioxidant properties of the cereals were significantly stronger than that of control after fermented by ABM. The improvement degrees of sorghum in DPPH radical scavenging capacity and superoxide anion radical scavenging ability were the highest, the improvement degrees of wheat in reducing power and ferrous ion chelating ability were the highest.     

Clearfield® rice: Its development,success, and key challenges on a global perspective

Weedy rice (Oryza sativa) is a close relative of domesticated rice and a noxious weed prevalent in rice fields in world regions where rice is grown. Weedy rice management has remained challenging to farmers, mainly due to the weed's physiological and morphological resemblance to rice cultivars. The introduction of Clearfield^® rice provides an alternative solution and an additional tool for integrated weed management. Clearfield^® rice-based programs result in the cleanest rice fields in the southern U.S. However, persistent application of the imidazolinone herbicides (imazethapyr, imazamox, and imazapic) in Clearfield^® rice raises concerns about the possible evolution of resistance to ALS-inhibitor herbicides in weedy rice and the transfer of resistance trait. The risk of resistant weedy rice evolution is much higher in Asia, Latin America, and other tropical regions where there is no winterkill and rice is planted at least twice each year. Herbicide carryover to rotational crops is also a concern. We summarized the progress of commercialization of Clearfield^® rice in 15 countries across the continents of America, Asia and Europe. In some countries, imidazolinone-resistant weedy rice outcrosses have been found abundant, thereby negating the utility of Clearfield^® technology. The persistence of imidazolinone herbicide residues in the soil is a concern in regions where multiple crops are planted in a year, or the following year. These challenges should be anticipated by countries that are considering adopting Clearfield^® rice technology. Issues associated with gene escape, resistance evolution in weedy rice, and herbicide carryover to rotational crops remain to be resolved. Research to achieve sustainable solutions for weedy rice management, must be continued and intense educational programs for growers must be sustained.