Effects of Packaging Method and Grade Size on Storage Quality of Newly Harvested Peanuts

Newly harvested and cured cv. Florunner jumbo (>8.33 mm dia), split (>6.75 mm dia) and no. 1 (<7.14, >6.35 mm dia) peanuts were packaged as shelled seed in plastic bags, CO₂ atmosphere; in burlap bags, and as farmers stock, bulk. After 1, 3 and 6 mo ambient storage, they were tested for moisture, color of raw seed-coat and color and flavor of peanut butter. Packaging showed no effect on flavor, but seed size did. No. 1's showed a linear loss of flavor with time and generally had the highest moisture level and produced the darkest butter. After 6 mo, burlap-bag storage yielded the darkest raw seed coats, while plastic bag-CO₂ generally maintained the highest moisture level and produced the darkest butter.     

Comparison of Flavor Quality of Peanut Based Pastes and Peanut Butter by Sensory Methods

A bland flavored and light colored paste was developed to increase utilization of peanuts. This study compared flavor quality of two pastes prepared from whole and chopped peanuts, water extracted to remove flavor precursors, two commercial samples of peanut butter and a paste from raw peanuts (control). Cluster analysis was used to compare sensory scores of all samples. The premium brand peanut butter had the strongest roasted flavor while the pastes had significantly more of the beany flavor than the peanut butters but less than that in the raw control. Chopping of kernels results in the loss of roasted and sweet flavors and the introduction of cardboard, musty and metallic flavors.     

Effect of superheated-steam roasting on physicochemical properties of peanut (<Emphasis Type="Italic">Arachis hypogea</Emphasis>) oil

Peanut (Arachis hypogaea) is an important source of protein and lipid globally. The effect of superheated-steam roasting on quality of peanut oil was evaluated based on physicochemical quality parameters. Three roasting temperatures (150, 200, and 250 °C) were used for different periods of roasting time and the obtained results were compared with those of conventional roasting. At 250 °C, superheated-steam roasted peanuts yielded more oil (26.84%) than conventionally roasted peanuts (24.85%). Compared with conventional roasting, superheated-steam roasting resulted in lower oil color, peroxide, p-anisidine, free fatty acid, conjugated diene and triene, and acid values and higher viscosity and iodine values in the roasted peanut oil. These values were significantly different from each other (p < 0.05). The fatty acids in roasted peanut oils were affected by roasting temperature and time for both the roasting modes. The superheated steam technique can be used to roast peanuts while maintaining their favorable characteristics.     

Determination of Pyrazine and Flavor Variations in Peanut Genotypes During Roasting

ABSTRACT: During peanut roasting, pyrazine compounds correlate highly with roasted flavor and aroma. Although roast color measurement is used to predict roasted flavor in peanuts, there are known variations between roast color and flavor development among genotypes. A method for measuring pyrazines using headspace solid‐phase microextraction (SPME) was developed and 4 peanut genotypes were roasted and analyzed under a variety of time‐temperature combinations. Peanut genotypes differed in roasted flavor and aroma, regardless of roast color. Florida MDR 98 formed the highest levels of pyrazines under the same roasting conditions, followed by Florunner, Georgia Greene, and SunOleic 97R, respectively. Of all pyrazines tested, 2,5‐dimethylpyrazine was most highly correlated to roasted peanut flavor and aroma.     

Color and Volatile Analysis of Peanuts Roasted Using Oven and Microwave Technologies

Roasted peanut color and volatiles were evaluated for different time and temperature combinations of roasting. Raw peanuts were oven roasted at 135 to 204 °C, microwave roasted for 1 to 3 min, or combination roasted by microwave and oven roasting for various times and temperatures. Volatiles were measured using selected ion flow tube mass spectrometry. L* values were used to categorize peanuts as under‐roasted, ideally roasted, and over‐roasted. The total roasting time in order to achieve ideal color was not shortened by most of the combination treatments compared to their oven roasted equivalents. Oven before microwave roasting compared to the reverse was found to significantly increase the L* value. Peanuts with the same color had different volatile levels. Hexanal concentrations decreased then increased with roasting. Pyrazine levels increased as roasting time increased, although oven at 177 °C treatments had the highest and microwave treatments had the lowest levels. Volatile levels generally increased as roasting time or temperature increased. Oven 177 °C for 15 min generally had the highest level of volatiles among the roasting treatments tested. Soft independent modeling of class analogies based on volatile levels showed that raw peanuts were the most different, commercial samples were the most similar to each other, and oven, microwave, and combination roasting were all similar in volatile profile.     

Effect of Peanut Butter Manufacture on Vitamin E

ABSTRACT: The effect of peanut butter manufacture on vitamin E originating from raw peanuts ( Arachis hypogaea L., runner-type) was determined. Tocopherols were quantified by normal-phase high-performance liquid chromatography. No significant differences were observed in tocopherol (T) values between 1998 and 1999 crop raw peanuts or between raw peanuts and peanut butter except for γ-T ( P > 0.05). Oil and stabilizer added to the roasted peanuts during peanut butter processing provided 4% of α-T in the finished peanut butter. Retention of total tocopherols during peanut butter manufacture was 95%. Mean α-T values (mg/100 g) of commercial peanut products ranged from 12.3 (peanut oil) to 4.1 (dry roasted peanuts).     

Effects of Hot Air-assisted Radio Frequency Heating on Quality and Shelf-life of Roasted Peanuts

Roasting is a critical step in processing peanut snack foods. The conventional roasting using hot air ovens has drawbacks of low production rate, poor product quality, and high energy cost. This study investigated the feasibility of using hot air-assisted radio frequency (RF) to roast dried salted peanuts. Physicochemical properties, volatile compounds, and sensory quality of the roasted peanuts were determined. The quality changes and shelf-life of vacuum-packaged roast peanuts stored under an accelerated shelf-life testing (ASLT) trial conducted at 20 and 50 °C were also evaluated. After 45 min roasting, moisture content of the salted peanuts reduced from initial 7.7 to 3.1 % and acid and peroxide values were 0.26?±?0.02 mg/g and 2.46?±?0.10 meq/kg, respectively, all in the levels associating with good quality of roasted peanuts. Sensory evaluation further validated the good quality of the roasted peanuts. Totally, 69 volatile compounds were identified in the roasted peanuts, in which 3 new volatiles were produced after about 13 weeks of storage. During the storage, relative concentrations of the favorable volatile compounds (mainly pyrazines and furan compounds) decreased in a certain degree, while the relative concentrations of some undesirable flavor compounds increased. The roasted peanuts had 31 weeks of shelf-life based on the industrial standard on the peroxide value. This study demonstrated that hot air-assisted RF roasting can produce high-quality roasted peanuts with prolonged shelf-life, thus, a new technology for the peanut roasting industry.     

Roasted Peanuts and Peanut Butter Quality are Affected by Supercritical Fluid Extraction

Roasted peanuts were extracted using supercritical CO₂ (413.6 bar, 50–60° for 0, 2 or 4 hr). Peanuts were evaluated for shatter, tristimulus color, shear-compression force, moisture, lipid content, and sensory attributes. Extracted nuts were prepared into peanut butter and evaluated for color, relative torque resistance ratio, and sensory attributes. Lipid content decreased from 51.6 to 40.6% during 4 hr extraction. SFE increased shatter, shear-compression force, and Hunter L-value, but decreased hue angle, roasted aroma intensity, moistness of mass, fracturability, and roasted flavor intensity of peanuts. SFE increased the relative torque resistance ratio, and adhesiveness of peanut butter but had little effect upon flavor. SFE may be useful to reduce peanut contaminants and lipids to produce value-added peanut products.     

SENSORY, CHEMICAL, AND PHYSICAL CHANGES IN INCREASED WATER ACTIVITY PEANUT BUTTER PRODUCTS

The effects of moisture, temperature, and storage time on the flavor characteristics of increased water activity peanut butter products were determined by sensory analysis. All three factors affected the sensory attributes of the products. At all temperatures and storage times, peanut butter products with 5.0% water added had lower roasted aroma and roasted flavor, with more off-odors and off-flavors than the 2.5% or 0.0% water added samples. Water activity and color were monitored throughout the study, and samples were evaluated for oxidation.     

Tocopherol content,peroxide value and sensory attributes in roasted peanuts during storage

The objective of this study was to determine changes in tocopherol content, peroxide value (PV) and sensory attributes from roasted peanuts during storage at 40 °C. There were no differences in tocopherol contents between roasted and raw peanuts except in α‐tocopherol content that decreased after roasting. All tocopherol contents decreased during storage. On the contrary, lipid oxidation indicators such as PV and the intensity ratings of oxidised and cardboard flavour increased during storage. On the other hand, the intensity ratings of roasted peanutty flavour decreased with storage time. Good correlations were observed between tocopherol contents and PVs. Tocopherol contents could be used as indicator of oxidative state in peanut products.     

Cadmium levels in peanut products.

Samples of peanut products such as peanut butter, raw, roasted and crushed peanuts from various commercial producers and obtained from local markets in Brisbane contained generally low levels of cadmium with mean values ranging from 0.013 to 0.031 mg/kg. These values were lower than the maximum permitted concentration for cadmium in peanuts in Australia, which is currently set at 0.05 mg/kg. Pre-digestion of samples using a microwave digestion system was found to be very effective in reducing digestion time prior to dry ashing for the analysis of cadmium.     

Modeling of Roasted Peanut Flavor for Some Virginia-Type Peanuts from Amino Acid and Sugar Contents

Prediction of sensory scores of roasted peanuts through analysis of the chemical components of raw peanuts is a goal of current research. Thirty samples of Virginia-type peanuts selected for wide variation in flavor precursors (amino acids and sugars) were roasted and evaluated by the Critical Laboratory Evaluation Roast (CLER) technique and by a flavor profile panel. Stepwise MAXR procedure was used to develop mathematical models for predicting both CLER scores and roasted peanut flavor ratings for the flavor profile. The best 10 variable model for predicting CLER scores had an R² of 0.969. A good fit (R²= 0.762) was obtained for predicting CLER score from only raw peanut data. The best 10 variable model for predicting roasted peanut flavor gave an R² of 0.928.     

Enzymatic and Autoxidation of Defatted Peanuts

Ground, blanched, raw, and roasted peanuts with varying oil contents were analyzed for oxidation products. Peroxide values (PV) of blanched, ground raw (BRAW) peanuts, demonstrating enzymatic oxidation, and heat-treated rancid roasted peanuts (RRST), demonstrating autoxidation, exhibited decreases (p ≦ 0.05) with decreasing oil content. The Oxidative Stability Index (OSI) time at 110 °C increased (p < 0.05) with decrease in oil content of raw (BRAW) and roasted (BRST) ground peanuts. A higher OSI indicated more oxidative stability, thereby supporting the hypothesis of higher potential for autoxidation at higher oil contents. In addition, BRST exhibited a shorter OSI than BRAW, indicating slower autoxidation in BRAW. Roasted peanutty odor, burnt odor, and roasted peanutty flavor, rancid/oxidized flavor, and burnt flavor scores of rancid roasted peanuts decreased (p ≦ 0.05) with decreasing oil content.     

Vitamin E and Oxidative Stability During Storage of Raw and Dry Roasted Peanuts Packaged under Air and Vacuum

ABSTRACT: The relationship between vitamin E and the oxidative stability of raw and dry roasted peanuts was studied during storage at 21°C under air and vacuum. Lipid oxidation was monitored by peroxide values (PVs) and conjugated diene values (CDVs). In air, PV (meq/kg) for roasted peanuts reached 47 by 12 wk, whereas that for raw peanuts was below 2 after 38 wk. Under vacuum, lipid oxidation was significantly retarded ( P < 0.05). Tocopherols of raw and roasted peanuts exponentially decreased with increasing PV. After 12 wk, about 50% of α-tocopherol (α-T) was lost for roasted peanuts under vacuum compared with about 90% under air. For raw peanuts, more than 70% of each tocopherol remained after 38 wk under air and vacuum. In general, α-T showed the least stability in roasted peanuts compared with other tocopherols under the reported storage conditions.     

'Flavor-fade' and Off-Flavors in Ground Roasted Peanuts As Related to Selected Pyrazines and Aldehydes

Headspace volatiles from ground roasted Florunner medium peanuts, stored at 65°C for 1–68 days, were separated and identifled by GC/MS. Selected pyrazines, resulting from Maillard browning and selected aldehydes from autoxidation were evaluated to determine their mechanistic contributions to peanut ‘flavor-fade.’ The 2,6-dimethylpyrazine, 2-methylpyrazine, 2-ethyl-5-methyl or 6-methylpyrazine, 2,3,5-trimethylpyrazine, and pentanal remained constant during storage (p < 0.05). Flavor scores for ‘roasted peanut’ decreased slightly, then leveled off and hex-anal, heptanal, octanal and nonanal increased during storage (p < 0.05). Oxidative ‘rancid’ flavor scores and thiobarbituric acid values also increased during storage (p < 0.05). Based on results, the ‘flavor-fade’ of stored roasted peanuts is due to masking of pyrazines and other ‘roasted peanut’ flavor compounds by large quantities of low-molecular weight aldehydes from lipid autoxidation, and not due to polymerization and/or degradation of the pyrazines.     

质谱法分析烘焙对花生过敏原Ara h 1潜在致敏性的影响

为研究烘焙对花生过敏原Ara h 1潜在致敏性的影响,采用高离液序列盐溶液从鲜花生和烘焙花生中提取总蛋白,通过十二烷基硫酸钠-聚丙烯酰胺凝胶电泳分析烘焙前后蛋白条带变化情况,并对其中的花生主要过敏蛋白Ara h 1条带进行质谱和Swiss-Model模型分析.十二烷基硫酸钠-聚丙烯酰胺凝胶电泳结果显示,烘焙花生蛋白出现...     

Effect of Temperature, Time and Number of Water Extractions on the Physicochemical and Flavor Characteristics of Peanuts

The effects of temperature, time, and number of extractions on the color, gas chromatographic profile, and flavor characteristics of water extracted peanuts were determined. Temperature was the major factor which affected these attributes. Increasing the extraction temperature resulted in darker colored peanuts with less chroma, less raw peanut flavor, and more cooked peanut flavor. It also led to a significant decrease in flavor volatiles. Based on the results, the recommended conditions are to water extract at 90°C for 10 min three times to produce peanuts which arc light in color and bland in flavor.     

风味花生粉常温储藏期间挥发性成分的变化与感官特性的关系探究

为探究风味花生粉储藏过程中挥发性成分对感官品质的影响,本文应用感官评价和仪器分析研究风味花生粉储藏过程中风味物质的变化及其对风味消褪的影响。首先通过气相色谱-嗅闻联用技术(GC-O)和气味贡献值(OAV)确定氧化变质的花生粉的风味活性物质,而后应用PLSR分析建立了风味活性物质与感官质量之间的相关性模型,找出了各个感官指标和具体的风味活性物质的显著相关性,掌握了风味花生粉的氧化规律。结果表明,21种风味活性物质中乙酸含量与各个感官质量评分、过氧化值(PV)、储藏时间均显著相关,壬醛含量与各个感官质量评分、过氧化值和储藏时间相关性均不显著;乙酸乙酯和香芹烯等与烤香味、甜香味正相关的物质在储藏过程中变化不显著;油脂氧化产生的醛、酮和酸等挥发性物质是焙烤花生独特风味的主要成分,储藏过程中氧化程度加剧是引起风味花生粉风味品质劣变的主要原因。