Analysis of Genotype,Environment, and Their Interaction Effects on the Phytochemicals and Antioxidant Capacities of Red Rice (Oryza sativa L.)

Fourteen red rice varieties were planted in two locations during summer (Hangzhou) and winter (Hainan) to study the effect of genotype and environment on the phytochemicals and antioxidant capacities of rice grain. B‐type proanthocyanidins in red rice were detected by LC‐MS/MS and quantified by using the vanillin assay. Analysis of variance showed that total phenolic content (TPC), total flavonoid content (TFC) and 2,2′‐azino‐bis‐(3‐ethylbenzothiazoline‐6‐sulfonic acid) (ABTS) radical scavenging capacity were mainly affected by environmental factors, which accounted for more than 60% of the total variance. However, total proanthocyanidin content (TPAC) and 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) radical scavenging capacity were equally affected by both genotype and environment. The genotype × environment effects were significant for all traits. The pairwise correlations among TPC, TFC, TPAC, ABTS, and DPPH were also significant (r > 0.900, P < 0.001). Principal component analysis identified the genotypes that had higher contents of antioxidants and more stability across environments. This study showed that indirect selection of a simple trait (i.e., TPC) is an effective way to select rice high in antioxidant capacity in breeding programs. This study also suggests that rice should be produced specifically in a certain environment for the end user to minimize the variation in the functional properties and maximize their contents.     

Effect of Ferulic Acid and Catechin on Sorghum and Maize Starch Pasting Properties

The effects of ferulic acid and catechin on starch pasting properties were studied as part of an investigation into the structure and functionality of phenolics in starch‐based products. Commercial maize starch, starches from sorghum cultivars (SV2, Chirimaugute, and DC‐75), and the phenolic compounds ferulic acid and catechin were used in the investigation. Pasting properties were measured using rapid viscosity analysis. Ferulic acid and catechin (up to 100 mg each) were added to maize or sorghum starch (3 g, 14% mb) in suspensions containing 10.32% dry solid content. Addition of catechin resulted in pink‐colored pastes, whereas ferulic acid had no effect on paste color. Ferulic acid and catechin decreased hot paste viscosity (HPV), final viscosity, and setback viscosity of maize and sorghum starch pastes, but had no influence on the peak viscosity (PV) of the former. Both phenolics increased breakdown viscosity. Ferulic acid had greater influence on HPV, final viscosity, breakdown, and setback than catechin. Addition of catechin under acidic conditions (pH 3) decreased HPV, final viscosity, and setback of maize starch, but alkaline conditions (pH 11) slightly increased setback. Both acidic and alkaline conditions resulted in increased breakdown. Investigations on model‐system interactions between ferulic acid or catechin and starch demonstrated that phenolic type and pH level both significantly influence starch pasting properties, with ferulic acid producing a more pronounced effect than catechin. The significance of these interactions is important, especially in food matrices where phenolics are to be added as functional food ingredients.     

Saskatoon and wild blueberries have higher anthocyanin contents than other Manitoba berries

Studies have shown that anthocyanins present in berry fruits have some beneficial health effects such as reducing age-associated oxidative stress and possessing anti-inflammatory properties. Therefore, six Manitoba berries (wild blueberry, Saskatoon berry, raspberry, chokecherry, strawberry, and seabuckthorn) were studied for their anthocyanin compositions (mg/100 g) on dry weight basis. Saskatoon berry and wild blueberry showed a high content of total anthocyanins (562.4 and 558.3 mg/100 g, respectively) that were not significantly (P>0.05) different from each other. The corresponding values for other berries: raspberry (365.2 mg/100 g), chokecherry (177.39 mg/100 g), and strawberry (97.5 mg/100 g) were significantly different from each other (P<0.05), and the total anthocyanin content of seabuckthorn was negligible (0.84 mg/100 g). Fifteen major anthocyanins were isolated from Manitoba berries. Saskatoon berry and wild blueberry contained higher amounts of delphinidin 3-glucoside (Dp-3-glc), malvidin 3-glucoside (Mv-3-glc), and malvidin 3-galactoside (Mv-3-gal). Dp-3-glc was 263.8 (mg/100 g) in Saskatoon berry and 84.4 (mg/100 g) in wild blueberry, whereas the corresponding values for Mv-3-glc in these berries were 47.4 and 139.6 (mg/100 g), respectively. Raspberry, strawberry, and chokecherry contained higher amounts of cyanidin 3-glucoside (Cy-3-glc), cyanidin 3-rutinoside (Cy-3-rut), and pelargonidin 3-glucoside (Pg-3-glc). The total anthocyanin content of Manitoba fruits followed the order: Saskatoon berry and blueberry (high anthocyanin berries), raspberry and chokecherry (medium anthocyanin berries), strawberry (low anthocyanin berries), and seabuckthorn (negligible anthocyanin berries). This study demonstrated that Saskatoon berries and wild blueberries have high potential value for fruit growers as well as the food and nutraceutical manufacturers because of their high anthocyanin contents.     

Antioxidant Capacity of Water‐Extractable Arabinoxylan from Commercial Barley,Wheat, and Wheat Fractions

The objective of this research was to analyze the antioxidant capacity directly of water‐extractable nonstarch polysaccharides (NSP) and feruloylated arabinoxylans (WEAX) following their characterization. NSP were isolated from barley, wheat, and wheat fractions (germ, bran, and aleurone). WEAX were extracted only from wheat fractions. Antioxidant capacity of NSP measured with the 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH), 2,2′‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulfonic acid (ABTS), and oxygen radical absorbance capacity (ORAC) assays was 24.0–99.0, 40.0–122.0, and 140.0–286.0μM Trolox equivalents (TE)/g, respectively. The antioxidant capacity of WEAX was 75.7–84.0, 58.0–105.0, and 110.0–235.0μM TE/g for those three assays. DPPH and ABTS were highly correlated to xylose content (R² = 0.85), degree of substitution (R² = −0.99), total phenolic acids (R² = >0.73), total phenolic content (TPC) (R² = >0.78), and ferulic acid content (R² = >0.86). ORAC was only influenced by TPC (R² = 0.63). By taking yield and antioxidant capacity into account, NSP would provide about 0.4–4.2, 0.6–5.1, and 2.8–12.0μM TE/g of flour of radical scavenging activity as measured by DPPH, ABTS, and ORAC, respectively, compared with WEAX (0.4–1.0, 0.3–1.3, and 0.6–2.8μM TE/g). Our results suggest that NSP or WEAX may play a role in protection against free radicals in a food matrix and likely in the gastrointestinal tract.     

Effect of Steeping Treatment on Pasting and Thermal Properties of Sorghum Starches

Chemical treatments in wet milling could improve the physico‐chemical properties of starch isolated from high‐tannin sorghums. Sorghums Chirimaugute (medium‐tannin), DC‐75 (high‐tannin), and SV2 (tannin‐free) were steeped in water, dilute HCl (0.9%, v/v), formaldehyde (0.05%, v/v), and NaOH (0.3%, w/v) solutions before wet milling and starch separation. Pasting, textural, and thermal properties of starch were determined. Steeping in NaOH resulted in starches with higher peak viscosity (PV), cool paste viscosity (CPV), and setback than when water, HCl, and formaldehyde were used. The time to PV (P_time) and PV temperature (P_temp) were markedly reduced by treatment with NaOH. NaOH could have caused a degree of pregelatinization. HCl treatment gave starches with higher P_temp and P _time, presumably due to delayed granule swelling. Gel hardness was largely determined by the starch amylase content. The low hardness of DC‐75 starch gels was slightly improved in NaOH‐treated grains. Gelatinization temperatures of sorghum starches were generally low, regardless of steeping treatment. Starch from NaOH‐treated grain generally had slightly higher gelatinization temperatures than when water, HCl, or HCHO was used. Chemical treatments during steeping of sorghum grains greatly affected starch properties. Dilute alkali steeping during wet milling could be used to improve properties of starch isolated from tannin‐containing sorghums.     

Noodle Quality as Related to Sorghum Starch Properties

Starch was extracted from 10 sorghum genotypes and physicochemical properties (amylose content and pasting, textural, and thermal properties) were evaluated. The amylose content was 24–30%. DC‐75 starch had the highest peak viscosity (380 Rapid Visco Analyser units). Gelatinization peak temperature occurred over a narrow range (67–69°C). Genotypes Kasvikisire and SV2 produced white starches. Starches from other genotypes were different shades of pink. The starch noodles prepared were, accordingly, either white or pink. Cooking enhanced the pink coloration of noodles. Cooking loss, noodle rehydration, and elasticity were evaluated. Cooking loss was low (mean 2.4%). Noodle elasticity was highly correlated with starch pasting properties of hot paste viscosity (HPV) (r = 0.81, P < 0.01) and cold paste viscosity (CPV) (r = 0.75, P < 0.01). Noodle rehydration was significantly correlated to the initial swelling temperature of starch (T_i) (r = ‐0.91, P < 0.001) and gelatinization peak temperature (T_p) (r = 0.69, P < 0.05). The findings suggest a potential area of food application for sorghum genotypes of different grain colors. Evaluation of starch properties could be a good starting point for selecting sorghum genotypes with superior noodle‐making properties.     

Genetic and Environmental Variation in Sorghum Starch Properties

Starch was isolated from eight local Zimbabwean landrace varieties, an improved cultivar (SV2) and a hybrid (DC-75) of sorghum grown in four environments. Amylose content, pasting (peak (PV), hot-paste (HPV), cool-paste (CPV) viscosity), textural and thermal (gelatinisation peak temperature (T_p) and gelatinisation energy (ΔH)) properties of the starches were determined. The F -tests from analyses of variance detected significant (p<0·001) differences among genotypes and growing environments for the starch properties measured. The results indicate that a range of genetic and environmental variability exists for these traits in sorghum genotypes although the latter could be greater than varietal effects. Hybrid DC-75 largely differed in starch amylose content, pasting PV, and gel hardness from the local landrace varieties. Environments used for local landrace varieties caused significant differences in starch properties, hence selection and monitoring of growing conditions is essential if a particular genotype is to maintain minimum variation in the desired pasting, textural or thermal properties. Genotype×environment interactions indicate that in breeding programmes, selection for starch properties at a single location would be misleading.     

C‐Glycosylflavone and Lignan Diglucoside Contents of Commercial,Regular, and Whole‐Wheat Spaghetti

Consumption of whole‐wheat products, including whole‐wheat spaghetti, is associated with beneficial health effects. Flavonoids and lignans are antioxidant phytochemicals that have received much attention from researchers. Investigations were conducted on the content of flavonoid glycosides, lignan diglucoside, and secoisolariciresinol diglucoside (SDG) as contributors to the health‐promoting properties of whole‐wheat spaghetti. Flavonoid glycosides present in regular and whole‐wheat spaghetti samples were identified as 6‐C‐glucosyl‐8‐C‐arabinosyl apigenin and the sinapic acid ester of apigenin‐C‐diglycoside while, in a previous study, the sinapic acid ester of apigenin‐C‐diglycoside was found only in wheat germ tissues. The content of these compounds was significantly higher in whole‐wheat spaghetti (17.0 and 15.1 μg of apigenin equivalent/g) compared to the regular brands (9.5 and 5.8 μg apigenin equivalent/g). SDG content was also significantly higher in whole‐wheat spaghetti (41.8 μg/g) compared to the regular brands (12.9 μg/g). These findings lend further support to the notion that phenolic compounds, along with dietary fiber, are concentrated in the bran layers of the wheat kernel; hence, consumption of whole grain products is strongly recommended to obtain significant levels of health‐promoting phytochemicals.     

Microwave-assisted extraction of bound phenolic acids in bran and flour fractions from sorghum and maize cultivars varying in hardness

To release bound phenolic acids, a microwave-assisted extraction procedure was applied to bran and flour fractions obtained from eight sorghum and eight maize cultivars varying in hardness. The procedure was followed by HPLC analysis, and the identities of phenolic acids were confirmed by MS/MS spectra. The extraction of sorghum and maize bound phenolic acids was done for 90 s in 2 M NaOH to release ferulic acid and p-coumaric acid from bran and flour. Two diferulic acids, 8-O-4'- and 8-5'-benzofuran form, were identified and quantitated in sorghum bran, and only the former was found in maize bran. The contents of ferulic acid and diferulic acids in sorghum bran were 416-827 and 25-179 μg/g, respectively, compared to 2193-4779 and 271-819 μg/g in maize. Phenolic acid levels of sorghum were similar between hard and soft cultivars, whereas those of maize differed significantly (p < 0.05) except for ferulic acid in flour. Sorghum phenolic acids were not correlated with grain hardness as measured using a tangential abrasive decortication device. Maize ferulic acid (r = -0.601, p < 0.01), p-coumaric acid (r = -0.668, p < 0.01), and 8-O-4'-diferulic acid (r = -0.629, p < 0.01) were significantly correlated with hardness.