Koushik Adhikari

Changes in the Profile of Genistein, Daidzein, and Their Conjugates during Thermal Processing of Tofu†

Profiles of genistein, daidzein, genistin, daidzin, and their acetyl- and malonyl-beta-glycosides were determined in tofu as affected by temperature and time. Tofu was heated in water at 80, 90, and 100 degrees C for 0 (control), 10, 20, 30, and 40 min, and the contents of the isoflavones of interest were quantified using reversed-phase HPLC. Total isoflavone content decreased most likely due to leaching of isoflavones into the water. Because the content of the isoflavones of the genistein series was little affected by the treatments, the decrease in the total isoflavone content was almost exclusively due to a decrease of the daidzein series. Changes in the profile of the daidzein series suggest little decarboxylation of the malonylglycoside to the acetylglycoside, but considerable de-esterification of the malonyl- and acetylglycoside to the beta-glucoside. Strongly temperature dependent decreases of the aglycon suggest possible thermal degradation of daidzein in addition to losses due to leaching.

Sensory and physicochemical characterization of juices made with pomegranate and blueberries, blackberries, or raspberries.

UNLABELLED The quality parameters of 1 commercial pomegranate juice mixed with 5 different concentrations of blueberry, blackberry, or raspberry juices were studied. The pH, total soluble solids content, titratable acidity, and total phenolic content were determined. To understand the aroma differences of the juices, solid phase microextraction-gas chromatography-mass spectrometry was used to determine the volatile compounds present in the mixtures. A consumer study also was carried out to relate consumer ratings to the instrumental data and to determine acceptance and possible modifications of the designed juices. Four juices received the highest scores in overall consumer liking: pomegranate/blueberry juice with 20% and 50% of blueberry, pomegranate/blackberry with 10% of blackberry, and pomegranate/raspberry with 10% of raspberry. The main characteristics in these juices were: a high maturity index (from 13.9 to 16.5), low acidity (0.79 to 1.09 g citric acid 100 per milliliter juice), and the presence of aromatic compounds typical in blueberries such as 6-methyl-5-hepten-2-one, α-terpineol, and E-nerol. The total phenolic content was significantly higher in the pomegranate/blackberry 90%/10% sample, raising around 3500 mg gallic acid equivalents per liter, and could be a positive determinant for consumers interested in purchasing healthful products. PRACTICAL APPLICATION The data presented in this article will help the juice industry, in the United States and elsewhere, to understand the consumers preferences for pomegranate blended juices. Pomegranate juices have high antioxidant content, which makes these juices more desirable for the health-conscious consumer of today.

Consumer palatability scores, sensory descriptive attributes, and volatile compounds of grilled beef steaks from three USDA Quality Grades

Consumer palatability scores, sensory descriptive attributes, and volatile compounds were assessed for beef Longissimus lumborum steaks of USDA Prime, Low Choice, and Standard grades. Overall and flavor liking was greater (P<0.05) for Prime and Low Choice. Initial flavor impact and fat-like attributes were greater (P<0.05) among Prime and Low Choice. Prime had greater (P<0.05) brown/roasted, beef identity, overall sweetness, and umami. Cardboard was greater (P<0.05) in Standard. Volatile compounds representing flavor development pathways were varied with quality grade. Standard had greater (P<0.05) abundances of n-aldehydes. Phenylacetaldehyde was greater (P<0.05) in Prime and Low Choice. Both 2,3-butanedione and 3-hydroxy-2-butanone were greatest (P<0.05) in Prime. Overall liking was positively correlated with many descriptive attributes, 3-hydroxy-2-butanone, and phenylacetaldehyde, and negatively correlated with cardboard, green, and n-aldehydes. While the measured attributes and volatiles may not be causative of flavor, this data indicates potential for prediction of flavor through their measurement.

Volatile Aroma Compounds in Various Brewed Green Teas

This study identifies and semi-quantifies aroma volatiles in brewed green tea samples. The objectives of this study were to identify using a gas chromatograph-mass spectrometer (GC-MS) paired with a headspace solid-phase micro-extraction (HS-SPME) the common volatile compounds that may be responsible for aroma/flavor of the brewed liquor of a range of green tea samples from various countries as consumed and to determine if green teas from the same region have similarities in volatile composition when green tea samples are prepared for consumption. Twenty-four green tea samples from eight different countries were brewed as recommended for consumer brewing. The aroma volatiles were extracted by HS-SPME, separated on a gas chromatograph and identified using a mass spectrometer. Thirty-eight compounds were identified and the concentrations were semi-quantified. The concentrations were lower than those reported by other researchers, probably because this research examined headspace volatiles from brewed tea rather than solvent extraction of leaves. No relationship to country of origin was found, which indicates that other factors have a greater influence than country of origin on aroma.

Volatile Compounds in Dry Dog Foods and Their Influence on Sensory Aromatic Profile

The aim of this study was to determine volatile compounds in dry dog foods and their possible influence on sensory aromatic profile. Grain-free dry dog foods were compared to dry dog foods manufactured with grain, but also with different protein sources for their aromatic volatiles. Solid-phase microextraction/gas chromatography/mass spectrometry was used to determine the aromatic compounds present in the headspace of these samples. Partial Least Squares regression was performed to correlate the instrumental aromatic data with the descriptive aroma analysis data. A total of 54 aromatic compounds were tentatively identified in the dry dog food samples, with aldehydes and ketones being the most represented organic volatiles group. Grain-added products were on the average higher in total volatiles than grain-free products. Partial Least Squares regression analysis indicated possible connections with sensory aromatic profile and grain-added samples, such as rancid aroma and aldehydes, especially hexanal. The results of this study showed that dry dog foods are products with complex odor characteristics and that grain-free products are less aromatic.

Recent developments in identifying and quantifying emotions during food consumption

Emotions and the consumption of food and beverages are inextricably intertwined. As the fields of sensory and consumer science seek to better conceptualize the consumer experience, interest in emotion measurement is growing. Emotions can provide key information to differentiate between products and predict consumer choice as well as give more detail about product perception. There are several emotion measurement instruments, including physiological methods and facial recognition, self-reported verbal emotion measurement and self-reported visual emotion measurement. This review discusses the purpose of measuring emotions, what is the definition of an emotion, what different instruments are available, and touches upon some promising research to deepen the connection between food and emotions.

Rice-Shaped Extruded Kernels: Physical, Sensory, and Nutritional Properties

Rice-shaped kernels were produced from micronutrient-fortified blends of corn and wheat flours, sorghum and wheat flours, or rice flour alone using a pilot-scale twin screw extruder. The color of extruded kernels from rice flour was similar to that of natural rice grain, but other treatments had significant color differences. Sorghum/wheat kernels had the highest cooking loss (13.4%) and water uptake (137.8%), and were also significantly different from other treatments with regard to instrumental texture profile and descriptive analysis. Vitamin C retention in extruded kernels was the lowest, ranging from 4.3 to 27.6%, whereas iron and folic acid had high stability.

Relation between developmental stage, sensory properties, and volatile content of organically and conventionally grown pac choi (Brassica rapa var. Mei Qing Choi).

UNLABELLED This study was conducted to identify and quantify the sensory characteristics and chemical profile of organically and conventionally grown pac choi (Brassica rapa var. Mei Qing Choi), also called bok choy, at 3 stages of growth (2.5, 4.5, and 6.5 wk). Sensory and instrumental data were correlated using partial least squares regression. Pac choi was grown in late spring. Descriptive sensory analysis was conducted by a highly trained panel and compounds were identified and quantified using a gas chromatograph/mass spectrometer. The findings of the study indicate that the differences in sensory characteristics and chemical profiles among stages of growth are more substantial than the differences between organic and conventional production. Green-unripe, musty/earthy, lettuce, and sweet flavors are representative in pac choi at early stages of growth. When older, pac choi has higher intensities of green-grassy/leafy, bitter, cabbage, and sulfur flavors that are associated with the increase of (Z)-3-hexen-1-ol, octyl acetate, 1-nonanol, 2-decanone, 1-penten-3-ol, linalool, camphor, menthol, isobornyl acetate, geranylacetone, and cedrol compounds. Conventional pac choi was higher than organic pac choi in green overall, bitter, and soapy flavors only at 2.5 wk of age. This may be associated with the presence of (Z)-3-hexenal, 2-hexyn-1-ol, and (E)-2-hexenal compounds. PRACTICAL APPLICATION The increased popularity of organic production has amplified the need for research that will help in understanding how this production system affects the final quality of food products. This study suggests that the stage of development has a much larger impact on sensory quality than organic or conventional growing of pac choi. Findings from this study promote consumer choice by showing that comparable sensory quality can be obtained using either production system, making the ultimate choice not only based on sensory quality but consumer choice related to environmental beliefs or economics.

Changes in the Sensory Characteristics of Mango Cultivars during the Production of Mango Purée and Sorbet

UNLABELLED The effects of processing on the flavor and texture properties of 4 mango cultivars available in the U.S. were studied. Descriptive panelists evaluated fresh mango, mango purée, and mango sorbet prepared from each cultivar. Purées were made by pulverizing mango flesh, passing it through a china cap, and heating it to 85 °C for 15 s. To prepare the sorbets, purées were diluted with water (1:1), sucrose was added to increase the total soluble solids (TSS) to 32 ± 2 °Brix, and bases were frozen in a batch-type ice cream freezer. Processing fresh mangoes into mango purée generally decreased fruity character and mango identity and led to the appearance of a cooked note. Many of the flavor distinctions among cultivars carried over from fresh to purée samples, but much of the texture variation was lost. Thermal processing had differing effects on the flavor of the cultivars, and therefore, results suggest that mango cultivars for purées should be selected based on properties after thermal treatment. Processing purées into sorbets minimized flavor variation among cultivars, although Tommy Atkins sorbet was relatively high in green and green-viney character and low in caramelized flavor compared to the other cultivars in sorbet. Based on the current study only very distinct flavor properties of mango cultivars may carry over to sorbets. PRACTICAL APPLICATION Findings from the present study will help mango purée and sorbet manufacturers select appropriate cultivars for their products by understanding the transformation that mango undergoes as it is processed into mango purée and subsequently to mango sorbet.

Extrusion Research for Addressing the Obesity Challenge

Extrusion is an important technology for processing grain-based products and adds immense value to raw materials ranging from corn, wheat, and rice to sorghum, oats, and soybeans. These raw materials can be in the form of whole-grain flours, dehulled flours, starches, concentrated or isolated cereal and legume proteins, or bran. Extrusion has been used for industrial applications such as rubber and plastics since the late 19th century and has been applied to food products since the 1930s. This technology has gained widespread use in the food industry because of its several benefits, including its economics and versatility. Today extruded products comprise a multibillion dollar market in the United States alone. These products include foods such as breakfast cereals, savory snacks, pastas, confectioneries, and texturized vegetable proteins, as well as products for animal consumption such as pet foods and aquatic feeds.