Effect of high-oleic trait and paste storage variables on sensory attribute stability of roasted peanuts

There has been much interest in the effect of the high-oleic acid trait of peanuts on various quality factors since discovery of high levels of oleic acid in a peanut mutant genotype. The trait provides greater oxidative stability for the high-oleic oil and seed. Several research groups have investigated high-oleic peanut oil and roasted peanut flavor characteristics, which were similar within high-oleic lines compared to Florunner. It was observed that some high-oleic lines derived from the Sunrunner cultivar have consistently higher predicted breeding values for roasted peanut attribute than Sunrunner itself. This study investigated if this apparent effect of the trait was an artifact arising from the handling procedures during processing and storage or from flavor fade. High-oleic lines used were derived by backcrossing the trait into existing cultivars, and the comparison of sensory attribute intensity was with the recurrent parent used in backcrossing. Previous comparisons have been between lines differing in more than just oleate content, that is, with widely different background genotypes that could contribute to the differences observed. Differential rates of change in sensory attributes were found in different background genotypes, suggesting that the comparison of high- and normal-oleic lines should be made in common background genotypes as well as in common production and postharvest environments. There was no measurable change in roasted peanut attribute in samples stored at -20 degrees C over the 63 day duration of this experiment. There were changes in roasted peanut in samples stored at 22 degrees C, confirming that storage at -20 degrees C is sufficient for large studies that require multiple sensory panel sessions over a period of weeks.     

Effect of the high-oleic trait on roasted peanut flavor in backcross-derived breeding lines

The high-oleic trait of peanut (Arachis hypogaea L.) has been suggested to have a positive impact on the roasted peanut sensory attribute. A series of lines derived by backcrossing the high-oleic trait into several existing cultivars were compared with their parent cultivars at locations in Florida, Georgia, North Carolina, and Texas. Breeders grew their high-oleic lines and parents in three-replicate tests at one or two locations. The Florida high-oleic line F435-2-3-B-2-1-b4-B-B-3-b3-b3-1-B was grown at each location. The test included normal- and high-oleic variants of F435, GK 7, NC 7, NC 9, Sunrunner, Tamrun 96, and Tamspan 90. Sound-mature kernel samples were roasted, ground into paste, and evaluated by a sensory panel using a 14-point flavor intensity unit (fiu) scale. Background genotype had an effect (P < 0.01) on the heritable sensory attributes roasted peanut, sweet, and bitter. Oleate level had a positive effect on roasted peanut intensity, increasing it by 0.3 fiu averaged across all seven background genotypes. However, the magnitude of improvement varied across background genotypes. The high-oleic trait had no effect or increased the intensity of the roasted peanut attribute in each background genotype. The increase was greatest in Tamrun 96 (+0.6 fiu, P < 0.05) and Spanish genotypes Tamspan 90 (+0.4 fiu, P < 0.05) and F435 (+0.4 fiu, P < 0.10). A change of 0.5 fiu or more should be perceptible to consumers. Interaction between oleate level and background genotype was detected for sweet (P < 0.10) and bitter (P < 0.01) attributes. The trait had an increasing effect on the bitter attribute only in the background genotype of Tamspan 90 (+0.7 fiu, P < 0.01). There was a nonsignificant increase in bitterness in the other Spanish background genotype, F435. Changes in bitterness in runner- and Virginia-type backgrounds were close to zero. Incorporation of the high-oleic trait into peanut cultivars is likely to improve the intensity of the roasted peanut attribute, but it may also increase the bitter attribute in Spanish genotypes.     

Relationships of sweet, bitter, and roasted peanut sensory attributes with carbohydrate components in peanuts

Certain roasted peanut quality sensory attributes have been shown to be heritable. Currently the only means of measuring these traits is the use of a trained sensory panel. This is a costly and time-consuming process. It is desirable, from a cost, time, and sample size perspective, to find other methodologies for estimating these traits. Because sweetness is the most heritable trait and it has a significant positive relationship to the roasted peanut trait, the possible relationships between heritable sensory traits and 18 carbohydrate components (inositol, glucose, fructose, sucrose, raffinose, stachyose, and 12 unknown peaks) in raw peanuts from 52 genotypes have been investigated. Previously reported correlations among sweet, bitter, and roasted peanut attributes were evident in this study as well. Where there was positive correlation of total sugars with sweetness, there also was positive correlation of total sugars with roasted peanut attribute and negative correlation of total sugars with bitterness and astringency. The expected generalized relationship of total sugars or sucrose to sweetness could not be established because the relationship was not the same across all market-types. Further work is needed to determine the nature of the chemical components related to the bitter principle, which appear to modify the sweet response and interfere with the sensory perception of sweetness, particularly in the Virginia market-type. Also, certain carbohydrate components showed significant relationships with sensory attributes in one market-type and not another. These differential associations demonstrate the complexity of the interrelationships among sweet, bitter, and roasted peanut sensory attributes. Within two market-types it is possible to improve the efficiency of selection for sweetness and roasted peanut quality by assaying for total carbohydrates. On the basis of the regression values the greatest efficiency would occur in the fastigiate market-type and then the runner.     

Chemical and sensory properties of liquid beet sugar.

Sensory analysis and headspace gas chromatography-flame ionization detection (GC-FID) analysis of liquid sugars (sucrose) designated for food-industrial use were performed in order to elucidate which compounds are responsible for perceived off-odors and off-flavors in liquid sugar. The liquid sugar samples investigated had various kinds of off-odors and off-flavors that might influence the quality of any food product in which they might be used, such as a jam or a soft drink. The sensory scores for the different attributes and the levels of different volatile compounds as measured by GC were analyzed for correlation using partial least-squares (PLS) analysis. A link between sensory analysis and GC analysis was thereby established, and compounds critical for the odor and flavor were identified using MS (mass spectrometry). Approximately 10 compounds were found to be correlated with the defined sensory attributes. Among these compounds associated with the sensory attributes were dimethyl disulfide, 2,6-dimethylpyrazine, 4-methoxyphenol, and 2, 5-dimethylfuran.     

Sensory attribute variation in low-temperature-stored roasted peanut paste

Length of sample storage can become significant in sensory studies due to panel fatigue limitations and samples needed for a reasonable expectation of finding significant differences. In roasted peanut sensory studies samples are stored between -10 and -23 degrees C to prevent or retard changes. Studies of up to 13 months' duration have examined stability and slow-rate sensory changes. Sweet taste was relatively stable, whereas bitter and tongue burn attributes increased slightly. Stale taste increased, suggesting lipid oxidation was taking place even at -23 degrees C. Painty attribute did not increase until stale was >3. An increase in fruity attribute was unexpected. With increases in fruity and stale attributes a decrease in roasted peanut was expected. However, storage at -23 degrees C seems to stabilize the roasted peanut lability when compared to storage at -10 degrees C. Fruity and stale interactions with roasted peanut and lability of roasted peanut were shown to be three separate and identifiable effects on roasted peanut.     

High-oleic peanuts are not different from normal peanuts in allergenic properties

High-oleic peanuts are known for a high content of oleic fatty acid. However, it is not known whether high-oleic peanuts are different from normal chemistry peanuts in levels of allergenicity and end-product adducts (i.e., products cross-linked with proteins). For this purpose, four different peanut cultivars (Florunner, Georgia Green, NC 9, and NC 2) were evaluated and compared with high-oleic peanuts (SunOleic 97R). Adducts such as AGE/CML from Maillard reactions and MDA/HNE from lipid oxidation were determined, respectively, in ELISA, using polyclonal antibodies. Allergenicity was determined based on IgE binding and T-cell proliferation. Results showed that raw high-oleic peanuts were not different from normal peanuts in adduct levels. After roasting, CML and HNE levels remained unchanged, but an increased and similar amounts of AGE adducts were found in all peanuts. MDA also increased but not in high-oleic peanuts. This suggests that high-oleic peanuts are more stable to lipid oxidation than others during heating. Despite this, high-oleic peanuts did not differ from normal peanuts in IgE binding and T-cell proliferation. It was concluded that a high content of oleic fatty acid has no effect on peanut allergenicity and that high-oleic peanuts do not give a higher or lower risk of allergy than normal peanuts.     

Influence of year and planting date on fatty acid chemistry of high oleic acid and normal peanut genotypes

The effect of an early-, mid-, or late-season planting date on the fatty acid chemistry of four high oleic acid, one mid oleic acid, and five normal oleic acid peanut (Arachis hypogaea L.) genotypes was evaluated over a three year period. Oleic acid was also compared to other fatty acids and to indices of oil quality. High-oleic genotypes included SunOleic 97R, UF98326, UF99621, and 88x1B-OLBC1-6-1-3-1-b2-B with a mean oleic acid content between 77.8 and 82.5%. Florida MDR98, a mid-oleic cultivar, was intermediate in oleic acid chemistry (59.8-68.0%). The normal oil chemistry lines (Georgia Greene, Andru93, Florunner, 86x13A-4-2-3-2-b3-B, and UF97102) had an oleic acid content between 50.0 and 59.0%. The ratio of oleic to linoleic (O/L) was 18:1 to 51:1 for high-oleic lines and 1.7:1 to 3.5:1 for normal genotypes. When analyzed as a split-split plot in time, year had a highly significant effect (P < 0.001) on the eight main fatty acids, iodine value, ratio of unsaturated to saturated fatty acids (U/S), and percentage of saturated fatty acids. Thus, data were analyzed separately by year. Although genotypic effects were highly significant each year, planting date influenced oil chemistry in two of three years. During both 1999 and 2000, 11 of 12 variables were influenced by planting date and by genotype x planting date interactions. Iodine values were approximately 75 for high-oleic lines compared to 90-95 for normal genotypes. The highest correlations occurred for oleic acid (18:1) and linoleic acid (18:2) (r = -0.996) and for oleic and palmitic (16:0) acids (r = -0.959). Oleic acid was also inversely related to iodine value (r = -0.978) and to percentage saturation (r = -0.841).     

Biosensor measurements of polar phenolics for the assessment of the bitterness and pungency of virgin olive oil

Bitterness and pungency, sensory quality attributes of virgin olive oil, are related to the presence of phenolic compounds. Fast and reliable alternatives for the evaluation of sensory attributes and phenolic content are desirable, as sensory and traditional analytical methods are time-consuming and expensive. In this study, two amperometric enzyme-based biosensors (employing tyrosinase or peroxidase) for rapid measurement of polar phenolics of olive oil were tested. The biosensor was constructed using disposable screen-printed carbon electrodes with the enzyme as biorecognition element. The sensor was coupled with a simple extraction procedure and optimized for use in flow injection analysis. The performance of the biosensor was assessed by measuring a set of virgin olive oils and comparing the results with data obtained by the reference HPLC method and sensory scores. The correlations between the tyrosinase- and peroxidase-based biosensors and phenolic content in the samples were high (r = 0.82 and 0.87, respectively), which, together with a good repeatability (rsd = 6%), suggests that these biosensors may represent a promising tool in the analysis of the total content of phenolics in virgin olive oils. The correlation with sensory quality attributes of virgin olive oil was lower, which illustrates the complexity of sensory perception. The two biosensors possessed different specificities toward different groups of phenolics, affecting bitterness and pungency prediction. The peroxidase-based biosensor showed a significant correlation (r = 0.66) with pungency.     

Sodium azide induced high-oleic peanut (Arachis hypogaea L.) mutant of Virginia type

Less prone to oxidation than its conventional counterpart, high-oleic peanut (Arachis hypogaea L.) containing?≥?72% oleate and?<?8% linoleate is preferred by processors, seed sellers and consumers. Development of high-oleic peanut cultivars with suitable pod/seed size and shape may satisfy the need from food processors manufacturing whole kernel or halve products. In this study, a high-oleic Virginia type peanut mutant was identified through screening of a 15 mmol/L sodium azide mutagenized M3 population with near infrared spectroscopy. Sequencing of the mutated and wild type FAD2A/FAD2B genes detected 2 point mutations. The G448A mutation in FAD2A was the same as in previous reports, causing an amino acid change of D150N. G558A in FAD2B was a novel mutation, resulting in a stop codon and premature termination of protein synthesis. 16 promising lines with acceptable productivity and pod/seed characters have been tentatively bred, which will be evaluated further in yield tests with replications after seed increase.

     

花生种子自然老化对品质及发芽的影响

为解析花生种子自然老化过程中品质及发芽特性的变化特征,本研究以6个花生品种(系)为试材,通过测定种子发芽率、发芽势、氯化三苯基四氮唑(TTC)还原量、电导率等指标对老化花生种子的品质和发芽活力进行综合评价.结果表明,随着种子老化程度加深,不同品种(系)花生种子的5个发芽指标(发芽率、发芽势、发芽指数、活力指数和生长量)...     

Preference Mapping of Commercial Whole Wheat Breads

Whole wheat breads are becoming a dominant presence in the market; however, the sensory qualities that drive consumer liking have not been well described. The purpose of this study was to identify sensory attributes and consumer acceptance of commercial whole wheat breads. Six whole wheat breads were evaluated for 26 attributes by a trained panel (N = 8). Two distinct groups of attributes were noted for the breads: those that were sweet, moist, and sticky versus those with characteristics associated with whole wheat such as wheaty, earthy, and bitter. In the consumer panel (N = 75), three clusters were formed. Cluster 1 (n = 28) had higher mean hedonic scores for all attributes compared with the other clusters (P < 0.01), although these consumers did not distinguish well among samples. Significant differences were found in all attributes in clusters 2 (n = 33) and 3 (n = 14). Cluster 2 preferred samples with sweet flavors and moist, cohesive textures, whereas cluster 3 preferred samples with earthy, roasted, and whole wheat flavors. A portion of consumers appeared to prefer breads not only with sweet and moist characteristics but also with some of the more hearty attributes like roasted and fermented. These data may be useful in developing new whole wheat products.     

Multiple compound quality index for cold-smoked salmon (Salmo salar) developed by multivariate regression of biogenic amines and pH

Production of biogenic amines during chill storage of 12 lots of cold-smoked salmon was studied. These data allowed for a multiple compound quality index to be developed by multivariate regression (partial least square regression). The quality index was based on concentrations of cadaverine, histamine, putrescine, and tyramine and pH and showed good correlation with sensory assessments. Biogenic amines were indicators of spoilage rather than casual agents of spoilage off-flavors. Four different biogenic amine profiles were found at the time of spoilage in cold-smoked salmon. These were the results of differences in the spoilage microflora. Histamine was detected above regulatory limits but below toxic levels. Measurements of salt and dry matter for calculation of water phase salt could be substituted by rapid water activity measurements.