Preference Mapping of Domestic/Imported Jasmine Rice for U.S.-Asian Consumers

Dietary Fibre Impacts the Texture of Cooked Whole Grain Rice

Consumers' general preference for white rice over whole grain rice stems from the hardness and low palatability of cooked whole grain rice; however, strong links have been found between consuming a large amount of white rice, leading a sedentary lifestyle, and acquiring type 2 diabetes. This led us to formulate a new breeding goal to improve the softness and palatability of whole grain rice while promoting its nutritional value. In this study, the association between dietary fibre profiles (using an enzymatic method combined with high-performance liquid chromatography) and textural properties of whole grain rice (using a texture analyser) was observed. The results showed that a variation in the ratio of soluble dietary fibre (SDF) and insoluble dietary fibre (IDF) influenced the textural characteristics of cooked whole grain rice; found a strong association between SDF to IDF ratio and hardness (r = -0.74, p < 0.01) or gumminess (r = -0.69, p < 0.01) of cooked whole grain rice, and demonstrated that the SDF to IDF ratio was also moderately correlated with cohesiveness (r = -0.45, p < 0.05), chewiness (r = -0.55, p < 0.01), and adhesiveness (r = 0.45, p < 0.05) of cooked whole grain rice. It is suggested that the SDF to IDF ratio can be used as a biomarker for breeding soft and highly palatable whole grain rice of cultivated tropical indica rice to achieve consumer well-being. Lastly, a simple modified method from the alkaline disintegration test was developed for high-throughput screening of dietary fibre profiles in the whole grain indica rice samples.

Consumer Acceptance of Brown and White Rice Varieties

Rice is consumed as a staple food by more than half of the world's population. Due to a higher fibre and micronutrient content, brown rice is more nutritious than white rice, but the consumption of brown rice is significantly lower than that of white rice, primarily due to sensory attributes. Therefore, the present research aimed to identify the sensory attributes which drive liking of Australian-grown brown and white rice varieties. Participants (n = 139) tasted and scored (9-point hedonic scale) their liking (i.e., overall liking, aroma, colour and texture) of brown and white rice types of Jasmine (Kyeema), Low GI (Doongara), and Medium grain rice (Amaroo). In addition, participants scored aroma, colour, hardness, fluffiness, stickiness, and chewiness, on Just About Right Scales. A within-subjects crossover design with randomised order (William's Latin Square design) was used with six repeated samples for liking and Just About Right scales. Penalty analyses were applied to determine the relative influence of perception of sensory attributes on consumer liking of the rice varieties. Across all varieties, white rice was liked more than brown rice due to the texture and colour, and Jasmine rice was preferred over Low GI and Medium Grain. Rice texture (hardness and chewiness) was the most important sensory attribute among all rice varieties and aroma was important for driving of liking between white rice varieties.

Identification of volatiles and odor-active compounds of aromatic rice by OSME analysis and SPME/GC-MS

During cooking, aromatic rice has a pleasant and characteristic aroma, a relevant factor to add sale value and attract consumer interest. This work studied the volatile compounds of aromatic rice (IAC 500) aiming at identifying those responsible for the aroma and flavor of the cooked rice. The description of the aromatic notes of the IAC 500 rice was carried out by a trained and selected sensory panel, followed by olfactometry (OSME) and identification by GC-MS of the rice volatile compounds extracted by SPME. A total of 80 volatiles was sensorially perceived and/or detected in the chromatographic effluent, of which 65 were identified, 44 presented some odor, and 36 were odorless. Among the odorous compounds, 15 were not detected by GC-FID or GC-MS. This study confirmed the compound 2-acetyl-1-pyrroline as the impacting volatile compound to the aroma of aromatic rice since it presented a very low percentage of area in the chromatogram and a high odor intensity. Other 43 compounds presented odor in lower intensities, but also contributed to the overall aroma of IAC 500 rice. From the 11 aromatic notes mentioned by the trained panel (cooked vegetable/seed, corn, hominy, green, porridge, popcorn, fresh baked cake/bread, milk, caramel, tapioca flour and flower), eight were related to the volatile compounds responsible for their aroma.

Emotions Evoked by Colors and Health Functionality Information of Colored Rice: A Cross-Cultural Study

This study aimed to examine the emotional responses evoked by cooked colored rice and its health functionality information in both consumers who eat rice as a staple food and consumers who do not eat rice as a staple food. Specifically, Korean and American consumers were exposed to colored rice and its health functionality information and an emotion lexicon was generated and measured based on focus group interviews (FGI) and two online consumer surveys. In test 1, the emotions evoked by presentation of stimuli to Koreans (N = 10) and Americans (N = 10) were extracted through FGIs and the first online consumer survey (Koreans = 69; Americans = 68) and an emotion lexicon was generated. As a result, a total of 34 terms were confirmed. Test 2 was conducted during the second online consumer survey (capturing data from a total of 208 Koreans and 208 Americans), utilizing the terms generated in test 1. In this test, only the colors (CO) of colored rice were presented to one group, while colors and health functionality information (CO&H) were presented to the other group. The overall liking for stimuli in both countries was highly correlated with familiarity. Koreans showed significantly more familiarity and liking for CO of white and black CO rice, while Americans showed significantly more familiarity and liking for CO of white and yellow rice. Hierarchical cluster analysis was performed to categorize the emotion terms, and the emotion terms were sorted into the three clusters, “Positive”, “Negative”, and “New”, for both countries. Under informed conditions, the emotions became more positive, and emotions in the “New” cluster were evoked in both countries. The current study employed a cross-cultural approach to assess consumers’ emotional responses to colored rice and health functionality information. Our findings suggest that providing foods with preferred colors for each culture and providing sufficient information on the said foods will help to promote unfamiliar foods.

Effect of Geographical Indication Information on Consumer Acceptability of Cooked Aromatic Rice

Geographical indication (GI) labeling is used to represent information about specific geographical origins of target products. This study aimed at determining the impact of GI information on sensory perception and acceptance of cooked aromatic rice samples. Ninety-nine participants evaluated cooked rice samples prepared using each of three aromatic rice varieties both with and without being provided with GI information. Participants rated the acceptance and intensity of the cooked rice samples in terms of appearance, aroma, flavor, texture, and overall liking, and also reported how important the GI information was to them. The results showed that consumers rated the cooked rice samples higher in appearance and overall liking when provided with GI information. Interestingly, participants who valued “state-of-origin” information more highly exhibited increased hedonic ratings of cooked rice samples when provided with GI information, but not when no GI information was given. Participants provided with GI information rated flavor or sweetness intensities of cooked aromatic rice samples closer to just-about-right than those without such information. This study provides empirical evidence about how GI information modulates sensory perception and acceptance of cooked aromatic rice samples. The findings will help rice industry, farmers, and traders better employ GI labeling to increase consumer acceptability of their rice products.

Preference mapping of different water-to-rice ratios in cooked aromatic white jasmine rice

The volume of water is a key variable affecting texture and flavor attributes of cooked rice with a significant influence on consumer preference. The aim of this study was to determine the attributes driving consumer preference for rice cooked with different water-to-rice ratios. Descriptive analysis (DA) methodology was employed to profile aromatic white Jasmine rice and a consumer study was run to determine preference for water-to-rice ratios. A DA panel (n = 12) evaluated ten aroma, four taste and flavor, three texture, and six appearance attributes for aromatic white Jasmine rice cooked with four water-to-rice ratios (1.125:1, 1.5:1, 1.875:1, and 2.25:1). Rice consumers (n = 117) evaluated preferences of the same aromatic white Jasmine rice cooked with the aforementioned water-to-rice ratios. DA results revealed floral aroma, firmness, chewiness, coarseness, stickiness/cohesiveness, and fluffiness were significantly influenced by an increasing water-to-rice ratio. There was no significant effect of water-to-rice ratios on consumer preferences (χ² (3, 117) = 1.17; P = 0.76). Consumers were grouped into three clusters with similar preference patterns using agglomerative hierarchical clustering. External preference mapping techniques run on each consumer cluster determined the water-to-rice ratios 1.125:1 and 1.875:1 as having the largest appeal to heavy consumers of rice, split by preferences for fluffy or sticky cooked rice. The water-to-rice ratio 1.5:1 was not dominated by any single attribute or group of attributes, appealing to less frequent rice consumers. Therefore, the water-to-rice ratios 1.125:1, 1.5:1, and 1.875:1 should satisfy the broadest groups of Australian rice consumers. PRACTICAL APPLICATION: Rice, a high volume commodity can be cooked using a variety of methods and volumes of water. The findings of this research will help manufacturers market water-to-rice ratios, assisting consumers in identifying cooked rice for which they have a preference.

Development of a cooked rice model for bibimbap and resulting physico-digestive properties

A cooked rice model for bibimbap was developed using response surface methodology (RSM). The ratio of brown rice (X ₁), high amylose rice (X ₂) based on a white rice ratio of 1.0, and the ratio of water to total rice weight (X ₃), were independent variables. Stickiness (Y ₁), elasticity (Y ₂), and overall acceptability by sensory testing (Y ₃) of cooked rice were dependent variables. Optimal RSM conditions were white rice:brown rice:high amylose rice=1:1.07:0.56, and the ratio of water to total rice weight was 1.6. Coefficient of determination (R ²) values of response surface equations were 0.909, 0.930, and 0.956 for Y ₁, Y ₂, and Y ₃, respectively (p<0.05). Experimental values measured under optimal conditions coincided with predicted values. Rapidly digestive starch (RDS) and expected glycemic index (eGI) values determined using the optimized rice model were much lower than for control white rice only.

Comparison of physicochemical characteristics and consumer perception of rice samples with different countries of origin and prices

BACKGROUND

Rice is the only food item which is not liberalized in Korea. To prepare for future liberalization of the rice market in Korea, the physicochemical characteristics and consumer perception of four domestic rice samples were compared with those of 11 foreign rice samples. Additionally, the influences of country of origin (CO) and price on purchase intent (PI) and willingness to pay (WTP) were investigated.

RESULTS

Consumer acceptance of rice samples from Japan was generally higher than that of rice samples from other countries. In an informed test, PI was affected by price and CO, while WTP was affected mostly by price. The PI decreased with the price provided while the WTP increased. In a blind test, consumers evaluated PI and WTP according to sensory liking. The PI was higher in the informed test than in the blind test in all domestic samples. Generally, consumer acceptance was highly correlated with fat acidity (r = - 0.76), protein content (r = - 0.72), and b value (r = - 0.64) of the rice samples.

CONCLUSION

Further efforts to increase the quality of rice are recommended for survival in the global market after liberalization of rice, even though consumers showed loyalty for PI of domestic samples.

Relating raw rice colour and composition to cooked rice colour

BACKGROUND

The whiter the rice, the more it is preferred by consumers and the more value it has in the market place. The first objective of this study was to determine the interrelationships of raw colour, cooked colour, amylose content and protein content in rice. The second objective was to assess whether or not the colour of cooked rice can be predicted from raw rice colour in conjunction with amylose and protein contents.

RESULTS

Protein and amylose contents were not significantly correlated with the colour measurements for raw rice. Protein and amylose showed moderate, significant associations with L* and a* and a*, b* and C* respectively for cooked rice. Only the colour variable a* of cooked rice could be predicted using protein, amylose and raw rice colour with high enough precision to be useful, and this was only for modelling using samples cooked in the same manner (rice cooker). Cooking method (rice cooker versus excess water) affected the colour of cooked rice.

CONCLUSION

Being able to predict a* in cooked rice is likely of limited value. Only the model that used samples where postharvest handling conditions were controlled (US-grown rice) was able to predict C*, a more useful measure, and then with only moderate ability. L*, a measure of brightness/whiteness, was not predicted well by any of the models.

Flavor lexicon for sensory descriptive profiling of different rice types

Rice flavor is a significant factor in determining quality and consumer acceptability as exemplified by scented rice, which is highly favored and commands a price premium. Sensory descriptive analysis has primarily been performed to assess rice flavor characteristics, but these studies feature only a limited lexicon for characterizing specific flavors or the range of flavor types is limited. This study was undertaken to establish a descriptive lexicon with reference standards for describing the flavor properties of a broad spectrum of rice types and use the developed lexicon to characterize which sensory attributes are most important in rice flavor quality. A rice flavor lexicon consisting of 24 descriptive notes was developed and expanded by 8 trained sensory panelists to characterize the flavor of cooked rice differing in terms of forms, types, and specialty (n = 36). Of these 24 descriptive terms, 19 were aromatic notes and 5 were fundamental tastes and oral feeling factors. Eighteen aromatic terms were significantly present in most rice samples whereas some descriptors exhibited unique characteristics of a specific-rice type. Subsequent multivariate analysis indicated that 18 descriptive terms were required to fully understand the characteristics of rice flavor in greater details. This lexicon covered a wider range of rice samples than in the previous studies and will facilitate targeting the characteristic notes important to rice processors as well as producers.

On the quality of commercial boneless skinless broiler breast meat

This study was conducted to assess the overall quality of commercial broiler breast meat products representing several brands and various industry practices (that is, chilling or enhancement procedures). Six different broiler breast products were evaluated by 75 consumers for 11 attributes related to appearance, flavor, tenderness, and juiciness, including overall acceptance. Twenty-three sensory attributes representing basic taste, flavor, texture, and appearance were evaluated by 11 trained descriptive panelists. Tenderness of cooked meat was instrumentally predicted by the Meullenet-Owens razor shear (MORS). Water holding capacity (cook loss) of cooked meat was also evaluated, and color and pH of raw meat were determined. Significant variations in quality among products tested were reported, indicating a broad range of product quality in the marketplace. One air-chilled and 1 water-chilled/enhanced product were found to be most liked by consumers. Tenderness of products tested was rated in average between "neither tough nor tender" and "very tender" by consumers. Cook loss of the 2 air-chilled products (13.5% to 19.1%, respectively) was significantly lower than that of water-chilled products (18.7% to 24.1%). Partial least squares regression revealed that 4 sensory texture attributes (hardness, hardness of mass, cohesiveness of mass, and tooth pack) and 1 basic taste (sour) were the major attributes driving consumer overall liking of commercial broiler breast meat products.

Comparison of odor-active compounds from six distinctly different rice flavor types

Using a dynamic headspace system with Tenax trap, GC-MS, GC-olfactometry (GC-O), and multivariate analysis, the aroma chemistry of six distinctly different rice flavor types (basmati, jasmine, two Korean japonica cultivars, black rice, and a nonaromatic rice) was analyzed. A total of 36 odorants from cooked samples were characterized by trained assessors. Twenty-five odorants had an intermediate or greater intensity (odor intensity >or= 3) and were considered to be major odor-active compounds. Their odor thresholds in air were determined using GC-O. 2-Acetyl-1-pyrroline (2-AP) had the lowest odor threshold (0.02 ng/L) followed by 11 aldehydes (ranging from 0.09 to 3.1 ng/L), guaiacol (1.5 ng/L), and 1-octen-3-ol (2.7 ng/L). On the basis of odor thresholds and odor activity values (OAVs), the importance of each major odor-active compound was assessed. OAVs for 2-AP, hexanal, ( E)-2-nonenal, octanal, heptanal, and nonanal comprised >97% of the relative proportion of OAVs from each rice flavor type, even though the relative proportion varied among samples. Thirteen odor-active compounds [2-AP, hexanal, ( E)-2-nonenal, octanal, heptanal, nonanal, 1-octen-3-ol, ( E)-2-octenal, ( E, E)-2,4-nonadienal, 2-heptanone, ( E, E)-2,4-decadienal, decanal, and guaiacol] among the six flavor types were the primary compounds explaining the differences in aroma. Multivariate analysis demonstrated that the individual rice flavor types could be separated and characterized using these compounds, which may be of potential use in rice-breeding programs focusing on flavor.

Characterization of volatile aroma compounds in cooked black rice

Black rice ( Oryza sativa L.), an aromatic specialty rice popular in Asia, has a unique flavor, the volatile chemistry of which has not been reported. The objectives of this research were to study volatile profiles of cooked black rice and to characterize the odor-active compounds. Thirty-five volatile compounds were identified by gas chromatography-mass spectrometry using a dynamic headspace system with Tenax trapping. Aldehydes and aromatics were quantitatively in the greatest abundance, accounting for 80.1% of total relative concentration of volatiles. The concentration of 2-acetyl-1-pyrroline (2-AP) was high, exceeded only by hexanal, nonanal, and 2-pentylfuran. A total of 25 odor-active compounds, determined by gas chromatography-olfactometry, were applied to principal component analysis, demonstrating significant differences between a black and a traditional white rice cultivar in terms of aroma and explaining 93.0% of the total variation. 2-AP, guaiacol, indole, and p-xylene largely influenced the difference between the aroma in cooked black and white rice. 2-AP and guaiacol were major contributors to the unique character of black rice based on odor thresholds, relative concentrations, and olfactometry.

Relationships between NIR Spectra and Sensory Attributes of Thai Commercial Fish Sauces

Twenty Thai commercial fish sauces were characterized by sensory descriptive analysis and near-infrared (NIR) spectroscopy. The main objectives were i) to investigate the relationships between sensory attributes and NIR spectra of samples and ii) to characterize the sensory characteristics of fish sauces based on NIR data. A generic descriptive analysis with 12 trained panels was used to characterize the sensory attributes. These attributes consisted of 15 descriptors: brown color, 5 aromatics (sweet, caramelized, fermented, fishy, and musty), 4 tastes (sweet, salty, bitter, and umami), 3 aftertastes (sweet, salty and bitter) and 2 flavors (caramelized and fishy). The results showed that Thai fish sauce samples exhibited significant differences in all of sensory attribute values (p < 0.05). NIR transflectance spectra were obtained from 1100 to 2500 nm. Prior to investigation of the relationships between sensory attributes and NIR spectra, principal component analysis (PCA) was applied to reduce the dimensionality of the spectral data from 622 wavelengths to two uncorrelated components (NIR1 and NIR2) which explained 92 and 7% of the total variation, respectively. NIR1 was highly correlated with the wavelength regions of 1100 - 1544, 1774 - 2062, 2092 - 2308, and 2358 - 2440 nm, while NIR2 was highly correlated with the wavelength regions of 1742 - 1764, 2066 - 2088, and 2312 - 2354 nm. Subsequently, the relationships among these two components and all sensory attributes were also investigated by PCA. The results showed that the first three principal components (PCs) named as fishy flavor component (PC1), sweet component (PC2) and bitterness component (PC3), respectively, explained a total of 66.86% of the variation. NIR1 was mainly correlated to the sensory attributes of fishy aromatic, fishy flavor and sweet aftertaste on PC1. In addition, the PCA using only the factor loadings of NIR1 and NIR2 could be used to classify samples into three groups which showed high, medium and low degrees of fishy aromatic, fishy flavor and sweet aftertaste.