Consumer perception of extruded snacks containing brown rice and dried mushroom

Effects of mushroom type, seasoning and health benefit information (HBI) on consumers’ saltiness expectation, sensory liking, elicited emotions and purchase intent (PI) of extruded snacks were investigated. Five snacks were evaluated: straw mushroom (Volvariella volvacea) extrudates without (SME) or with seasoning (SMES), phoenix mushroom (Pleurotus pulmonarius) extrudates without (PME) or with seasoning (PMES), and the control without mushroom and seasoning. Hedonic scores and positive emotions were generally higher for seasoned mushroom-containing snacks (SMES and PMES) with 65% and 75.83% of consumers reporting willingness to purchase, respectively, after receiving HBI. Bored, interested and satisfied were identified as significant emotional predictors for PI odds. Flavour, saltiness, overall liking, bored, good and interested were critical attributes, differentiating snacks. This study demonstrated that sensory liking and PI of extruded brown rice-based snacks containing mushroom could be improved through savoury seasoning addition, which also allowed saltiness expectations to be met.     

Physicochemical property changes in germinated brown rice flour from different storage periods of paddy rice

This study revealed that the storage duration (2, 4, 6, 8, 10 and 12 months) of paddy rice and pH (3 and 6.8) of steeping water during germination were significantly influenced the physicochemical properties of germinated brown rice flour (GBRF). GBRF obtained at pH 3 vs. 6.8 provided the highest both reducing sugar content and free gamma‐aminobutyric acid (GABA) content (99.8 vs. 54.2 mg per 100 g flour respectively) as the paddy rice was stored for 8 months. The peak viscosity of GBRF obtained at pH 3 and 6.8 exhibited the lower values than that of non‐GBRF throughout the storage. From the principal component analysis, reducing sugar had a positive correlation with α‐amylase activity whereas a negative correlation was found with peak viscosity. GBRF from paddy rice stored for 8 months and germinated at pH 3 possessed the highest free GABA content, 50 times of the non‐GBRF, which can be further utilised in functional and healthy foods.     

Physicochemical Properties and Consumer Acceptance of Wheat-Germinated Brown Rice Bread during Storage Time

Abstract: Selected physicochemical properties and consumer acceptance of bread prepared from composite flour (wheat:germinated brown rice:germinated glutinous brown rice flours at 60:30:10 ratio) were evaluated during storage for 0, 3, and 5 d, and compared with wheat bread (0 d, control). During storage, color profiles and water activity (from 0.947 to 0.932) of crumbs of composite flour breads slightly changed, but moisture content drastically decreased along with increasing crumb hardness (from 4.16 N to 10.37 N). Higher retrogradation in bread crumb was observed particularly for 5-d stored bread (ΔH = 2.24 J/g) compared to that of the fresh composite bread and the control (ΔH = 0.70 and 0.51 J/g, respectively). Mean (n = 116) overall liking score of the fresh composite flour bread (0 d) was slightly lower than that of the control (7.1 compared with 7.6 based on a 9-point hedonic scale). At least 76% of consumers would purchase the fresh composite flour bread if commercially available. Breads were differentiated by textural (moistness, smoothness, and softness) acceptability with canonical correlation of 0.84 to 0.87. The signal-to-noise ratio values of the 5-d stored breads were lower than the control, due mainly to the non-JAR (not-enough) intensity responses for moistness, smoothness, and softness; the mean drop of liking scores for these attributes ranged from 2.42 to 2.98. Flavor acceptability and overall liking were factors influencing consumers’ purchase intent of composite flour breads based on logistic regression analysis. This study demonstrated feasibility of incorporating up to 40% germinated brown rice flour in a wheat bread formulation. Practical Application: Our previous study revealed that flours from germinated brown rice have better nutritional properties, particularly gamma-aminobutyric acid (GABA), than the nongerminated one. This study demonstrated feasibility of incorporating up to 40% germinated brown rice flour in a wheat bread formulation. In the current U.S. market, this type of bread may be sold as frozen bread that would have a longer shelf life, or may be supplied as a food-service product that would be made-to-order or made fresh daily as currently practiced in some major grocery stores.     

Germination Conditions Affect Selected Quality of Composite Wheat-Germinated Brown Rice Flour and Bread Formulations

Abstract: Brown rice has been reported to be more nutritious after germination. Germinated brown rice flours (GBRFs) from different steeping conditions (in distilled water [DI, pH 6.8] or in a buffer solution [pH 3] for either 24 or 48 h at 35 °C) were evaluated in this study. GBRF obtained from brown rice steeped at pH 3 for 48 h contained the highest amount of free gamma aminobutyric acid (GABA; 67 mg/100 g flour). The composite flour (wheat-GBRF) at a ratio of 70 : 30 exhibited significantly lower peak viscosity (PV) (56.99 – 132.45 RVU) with higher alpha-amylase activity (SN = 696 – 1826) compared with those of wheat flour (control) (PV = 136.46 RVU and SN = 1976). Bread formulations, containing 30% GBRF, had lower loaf volume and greater hardness (P < 0.05) than the wheat bread. However, the hardness of bread containing 30% GBRF (except at pH 6.8 and 24 h) was significantly lower than that of bread containing 30% nongerminated brown rice flour (BRF). Acceptability scores for aroma, taste, and flavor of breads prepared with or without GBRFs (30% substitution) were not significantly different, with the mean score ranging from 6.1 (like slightly) to 7 (like moderately). Among the bread formulations containing GBRF, the one with GBRF prepared after 24 h steeping at pH 3 had a slightly higher (though not significant) overall liking score (6.8). This study demonstrated that it is feasible to substitute wheat flour with up to 30% GBRF in bread formulation without negatively affecting sensory acceptance. Practical Application: Our previous study revealed that flours from germinated brown rice have better nutritional properties, particularly gamma-aminobutyric acid (GABA), than the nongerminated one. This study demonstrated feasibility of incorporating up to 30% germinated brown rice flour in a wheat bread formulation without negatively affecting sensory acceptance. In the current United States market, this type of bread may be sold as frozen bread which would have a longer shelf life. Further study is thus needed.     

Antimicrobial Activity of Cinnamaldehyde and Eugenol and Their Activity after Incorporation into Cellulose‐based Packaging Films

Cinnamaldehyde and eugenol were investigated for their antimicrobial activity against 10 pathogenic and spoilage bacteria and three strains of yeast, using an agar‐well diffusion assay. The minimum inhibitory concentrations (MICs) of these compounds were determined using an agar dilution method. Finally, cinnamaldehyde‐incorporated and eugenol‐incorporated methyl cellulose films were prepared to obtain active antimicrobial packaging materials. These antimicrobial cellulose‐based packaging films were investigated for antimicrobial activity against target microorganisms using both an agar‐disc diffusion technique and a vapour diffusion technique. At a concentration of 50 µl/ml, cinnamaldehyde and eugenol revealed antimicrobial activity against all test strains. They showed zones of inhibition, ranging from 8.7 to 30.1 mm in diameter. Eugenol and cinnamaldehyde possessed ‘moderate?strong inhibitory’ and ‘strong?highly strong inhibitory’ characteristics, respectively. With MICs of 0.78?50 µl/ml, cinnamaldehyde and eugenol also inhibited the growth of all test microorganisms. Among the test microorganisms, Aeromonas hydrophila and Enterococcus faecalis were the most sensitive to cinnamaldehyde and eugenol. Cinnamaldehyde showed lower MICs against all test strains than those of eugenol. In an agar‐disc diffusion assay, cellulose‐based film containing cinnamaldehyde or eugenol totally failed to exhibit a clear inhibitory zone. However, it showed positive activity against all selected test strains in terms of size and enumeration of microbial colonies in a vapour diffusion assay. This study shows the potential use of cinnamaldehyde and eugenol for application in antimicrobial packaging film or coating. Copyright © 2011 John Wiley & Sons, Ltd.     

Germination Conditions Affect Physicochemical Properties of Germinated Brown Rice Flour

ABSTRACT:  Germinated brown rice has been reported to be nutritious due to increased free gamma-aminobutyric acid (GABA). The physicochemical properties of brown rice (BR) and glutinous brown rice (GNBR) after germination as affected by different steeping times (24, 36, 48, and 72 h depending on the rice variety) and pHs of steeping water (3, 5, 7, and as-is) were determined and compared to those of the nongerminated one (control). As the steeping time increased or pH of steeping water decreased, germinated brown rice flours (GBRF) from both BR and GNBR had greater reducing sugar, free GABA and α-amylase activity; while the total starch and viscosity were lower than their respective controls. GBRFs from both BR and GNBR prepared after 24-h steeping time at pH 3 contained a high content of free GABA at 32.70 and 30.69 mg/100 g flour, respectively. The peak viscosity of GBRF obtained from both BR and GNBR (7.42 to 228.22 and 4.42 to 58.67 RVU, respectively) was significantly lower than that of their controls (255.46 and 190.17 RVU, respectively). The principal component analysis indicated that the important variables for discriminating among GBRFs, explained by the first 2 components at 89.82% of total explained variance, were the pasting profiles, α-amylase activity, and free GABA.     

Composite wheat–germinated brown rice flours: selected physicochemical properties and bread application

Selected physicochemical properties of composite [wheat/germinated brown rice (GBRF)/germinated glutinous brown rice (GGNBRF)] flours at 100:0:0 (control), 70:30:0, 60:30:10, 60:40:0 and 50:40:10 (%) were evaluated. Germination (steeping at pH 3 for 24 h at 35 °C) increased free gamma‐aminobutyric acid from 2.11 to 32.7 and 2.41 to 30.69 mg per 100 g flour for GBRF and GGNBRF, respectively. The 60:30:10 and 50:40:10 composite flours exhibited the lower peak viscosity (70.42 and 68.54 RVU, respectively). The setback viscosity of composite flours containing GGNBR was significantly lower than other flours. The presence of GBRF and GGNBRF significantly lowered specific volume and expansion ratio of breads. However, all sensory liking scores, except for appearance, were not significantly different among composite flour breads. Overall liking scores of all breads ranged from 6.8 to 7.2 (like moderately). This study demonstrated feasibility of incorporating GBRF and GGNBRF up to 50% by weight in bread formulations without compromising sensory liking.     

New insights on the characteristics of starch network

This study investigated the roles of granule-associated proteins (0.16% w/w d.b.) in mungbean starch (MBS, Vigna radiata (L) Wilczec) on the microstructural and thermo-mechanical properties of MBS gel and thermoplastic. Gelatinization at high water content (9–13% w/w) and intermediate water content (40–60% w/w) ranges generated microscopic multi-phase structure of swollen MBS granules, separated starch-rich phase and separated protein-rich phase. The presence of 50 mM calcium lactate plus 25 mM cysteine lowered the compressive stress of MBS gels at high water content range, increased T_o, T_p and T_e of MBS slurries at intermediate water contents, and lowered the storage modulus of the protein-rich phase in thermoplastic MBS at its T_g (P < 0.05). This study revealed the new insights on the significance of granule-associated proteins in the regulation of the envelope permeability, the leaching of starch and the thermo-mechanical characteristics of starch network over a wide range of water contents.     

Influence of interfacial composition on oxidative stability of oil-in-water emulsions stabilized by biopolymer emulsifiers

The objective of this research was to evaluate the influence of storage pH (3 and 7) and biopolymer emulsifier type (Whey protein isolate (WPI), Modified starch (MS) and Gum arabic (GA)) on the physical and oxidative stability of rice bran oil-in-water emulsions. All three emulsifiers formed small emulsion droplets (d₃₂ < 0.5 μm) when used at sufficiently high levels: 0.45%, 1% and 10% for WPI, MS and GA, respectively. The droplets were relatively stable to droplet growth throughout storage (d₃₂ < 0.6 μm after 20 days), although there was some evidence of droplet aggregation particularly in the MS-stabilized emulsions. The electrical charge on the biopolymer-coated lipid droplets depended on pH and biopolymer type: −13 and −27 mV at pH 3 and 7 for GA; −2 and −3 mV at pH 3 and 7 for MS; +37 and −38 mV at pH 3 and 7 for WPI. The oxidative stability of the emulsions was monitored by measuring peroxide (primary products) and hexanal (secondary products) formation during storage at 37 °C, for up to 20 days, in the presence of a pro-oxidant (iron/EDTA). Rice bran oil emulsions containing MS- and WPI-coated lipid droplets were relatively stable to lipid oxidation, but those containing GA-coated droplets were highly unstable to oxidation at both pH 3 and 7. The results are interpreted in terms of the impact of the electrical characteristics of the biopolymers on the ability of cationic iron ions to interact with emulsified lipids. These results have important implications for utilizing rice bran oil, and other oxidatively unstable oils, in commercial food and beverage products.