Whey Protein Coating Effect on The Oxygen Uptake of Dry Roasted Peanuts

A procedure was developed to coat peanuts with aqueous whey protein isolate (WPI) solutions based on increasing coating-solution viscosity. Oxygen uptake of WPI-coated nuts and uncoated nuts were compared. WPI coatings delayed oxygen uptake of dry roasted peanuts at intermediate (53%) and low (21%) storage relative humidity. They had similar results at 29°C and 37°C. The effects of coating thickness and storage relative humidity indicate that the mechanism of protection of the coatings was through their oxygen barrier properties.     

Maturity Effects on Sensory and Storage Quality of Roasted Virginia-Type Peanuts

Virginia-type peanuts from two yrs were studied to determine differences in sensory and storage characteristics of five mesocarp-color based maturity classes. Peanuts were roasted, stored at 37°C, and sampled over 12 wk to evaluate flavor and oil. Higher intensities of roasted peanutty and sweet and lower painty flavors were found in the most mature classes. Painty increased more quickly in immature classes. Oxidative stability and fatty acid profiles indicated this change. Immature peanuts had lower flavor impact and deteriorated faster. Distributions at progressive harvest dates indicated more immature peanuts in the Extra Large Kernel grade at early harvest. Variability in sensory characteristics of maturity classes and changes in their distribution in size-based commercial grades indicate a high potential for maturity related flavor variation between lots.     

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.     

三种香辛料水提物腌制对烤鸭腿脂质氧化和挥发性风味物质的影响

为研究不同浓度的(0.05%,0.1%)香叶(X0.05组、X0.1组)、高良姜(J0.05组、J0.1组)、花椒水提物(H0.05组、H0.1组)腌制对烤鸭腿挥发性风味物质和脂质氧化的影响,利用顶空固相微萃取-气质联用技术结合感官评价及相对气味活度值(Relative Odor Activity Value,ROAV)分析,并测定烤鸭腿中硫代巴比妥酸值(Thiobarbituric Acid Reactive Substances,TBARS)来评价其脂肪氧化程度。结果表明:与对照组(未添加香辛料水提物)相比,各香辛料水提物组的感官评分均无显著性差异;对照组烤鸭腿中的关键挥发性成分为1-辛烯-3-醇、己酸乙烯酯、壬醛、己醛、癸醛、辛醛。0.05%的香叶、高良姜、花椒水提物腌制能够较好地保持烤鸭腿中关键挥发性成分的种类和ROAV,0.1%的香叶、高良姜、花椒水提物腌制能够显著降低烤鸭腿中己醛、癸醛的ROAV,显著增加2-甲基丁酸甲酯的ROAV (P<0.05),而对关键挥发性成分的种类无明显影响;此外,各香辛料水提物组的TBARS值均显著降低(P<0.05)。总之,香叶、高良姜、花椒水提物腌制既能够有效抑制烤鸭腿中的脂质氧化,又不会对烤鸭腿的整体香味产生明显影响,这为香叶、高良姜、花椒水提物在烤鸭腿中的应用提供了一定的理论依据。     

Isolation and Identification of Volatile Compounds from Roasted Peanuts

Volatile flavor compounds were isolated from 70 kg of freshly roasted Florida Runner peanuts by a specially designed apparatus. The isolated volatile flavor compounds were subjected to extensive gas chromatographic fractionation and the pure fractions obtained were identified by infrared and mass spectrometry. A total of 131 compounds was identified. The following compounds are reported for the first time as flavor components of roasted peanuts: five lactones, incluing γ-crotolactone, 3-methyl-γ-crotolactone and 5-hydroxy-4-nonenoic acid, lactone; four pyrazines, three pyrroles; three pyridines, 13 sulfides, including three monosulfides, six disulfides and four trisulfides; seven thiazoles, two thiophenes, five furanoids, including 2-methyL3(2H)furanone; five oxazoles, three oxazolines, including 2-methyl-3-oxazoline; 12 hydrocarbons, one alcohol, one ketone, two acids, two esters, 2-acetoxy-2-butene, and maltol.     

Flavor and Oxidative Stability of Roasted High Oleic Acid Peanuts

A new peanut line has been developed at the University of Florida with about 80% oleic and 3% linoleic acid. Volatiles and sensory characteristics of roasted normal and high oleic acid peanuts stored at 25°C were compared. Volatiles were analyzed using adsorbent trapping and GCMS, a 20-member trained panel was used for sensory evaluation, and a GC sniffer port was used to evaluate odor characteristics of volatile isolates. Peroxide values were lower for high oleic (HO) peanuts than normal peanuts during storage at 25°C and 40°C. The hexanal content of the peanuts was higher for normal than HO. Peanutty flavor was more stable for HO than normal after 6 wk storage. Painty and cardboard flavors were higher in normal peanuts than HO during storage. Differences for both painty and cardboard flavors were significant after 6 wk storage. Pyrazines were more stable in HO peanuts. Shelf life was estimated from sensory data to be two times longer in HO peanuts.     

Edible Coating Effects on Fried Potato Balls

The effects of various treatments and frying times on some physical, chemical, and sensorial properties of potato balls coated with chickpea and wheat flour were studied. Potato balls were pre-dusted with chickpea flour (CF) or wheat flour (WF) as an initial coating which was followed by dipping into 0.1% xanthum gum solution as the second coating. The last coating was breading with 1:3 CF/WF, 1:1 CF/WF, and 3:1 CF/WF mixtures. Coated potato balls were fried at 185 °C for 5, 7, and 9 min. The pre-dusting materials, particularly the effect of CF, enhanced yield values and sensorial properties as well as increased adhesion degree as it decreased frying loss. Although, the breading materials raised the yield values compared to the control, the yield and moisture content values decreased with increasing frying time. Frying loss, fat absorption, penetrometer values, and texture values also increased. Results revealed that CF is suitable as a pre-dusting material, and 7 min was the more efficient frying time for coated potato balls.     

Effects of Sonication and Edible Coating Containing Rosemary and Tea Extracts on Reduction of Peanut Lipid Oxidative Rancidity

Rancidity due to the lipid oxidation process is a critical factor influencing the quality of roasted peanuts. Sonication in combination with edible coatings added with plant extracts may extend the oxidative stability of peanuts. Peanuts were roasted at 178°C for 15 min, subjected to sonication in hexane for 10 min, and then coated with carboxymethyl cellulose (CMC) solution mixed with rosemary, tea extracts, and α-tocopherol and stored at 35°C for 12 weeks. The oxidative stability of the samples was investigated by measuring the oxidative stability index. Reduction in oxidation of 66.1% and 10.4% was observed for samples roasted and coated with extracts of rosemary and tea, respectively, as compared to uncoated sample. However, the oxidative stability of samples roasted–sonicated and coated with extracts of rosemary and tea was improved by 100.7% and 28.1%, respectively, in relation to the control. Sonication beyond coating improved the oxidative stability of the samples mixed with rosemary, tea extracts, and α-tocopherol by 10.3%, 12.1%, 34.6%, and 17.7%, respectively. The L ^* , a ^* , and b ^* values indicated that the peanut coated with CMC mixed with rosemary, tea extracts, and tocopherol at different concentration levels did not have significant (P < 0.05) color change during the 12-week storage at 35°C.     

Edible Coating Effects on Storage Life and Quality of Tomatoes

Tomatoes at breaker and pink stage maturities were coated with comzein film. Color, weight and firmness changes and sensory quality were compared with noncoated tomatoes during storage at 21°C. Corn-zein fdm delayed color change and loss of firmness and weight during storage. Shelf life was extended by 6 days with film coatings as determined by sensory evaluation.     

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.     

Edible Coating Effects on Postharvest Quality of Green Bell Peppers

Green bell pepper fruits (Capsicum annuum L., cv. “Jupiter”) were coated with a mineral-oil-based coating or a cellulose-based coating. Three different milk-protein-based edible coatings (whey protein isolate, sodium caseinate, and sodium caseinate beeswax emulsion) plasticized with glycerol were also tested. The effects of these coatings were followed by measurement of changes in respiration, internal gases, color, firmness, and water loss during storage at 10°C, 80–85% RH for 20 days. None reduced respiration or affected color. Only the mineral-oil-based coating significantly reduced moisture loss, thus maintaining fruit firmness and thereby prolonging fruit freshness.     

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.     

辐照处理对泠却肉脂肪氧化影响的研究

研究了辐照剂量、贮藏时间和抗氧化剂对冷却肉脂肪氧化的影响。结果表明：辐照处理会加速冷却肉脂肪氧化，辐照剂量越高，脂肪氧化程度越大；在贮藏前期，随着贮藏时间的延长，辐照冷却肉脂肪氧化速度明显加快；在贮藏后期，冷却肉脂肪氧化的程度不能单纯根据过氧化值来判断；抗氧化剂茶多酚可以明显抑制辐照处理和贮藏时间对冷却肉脂肪氧化的影响。     

Effect of an Edible Collagen Film Overwrap on Exudation and Lipid Oxidation in Beef Round Steak

Beef round steak when wrapped with an edible collagen film (Coffi®) exhibited much less fluid exudate (P<0.05) than unwrapped controls. This was true in refrigerated and frozen/thawed samples with standard retail (permeable film overwrap) or vacuum (pouch) packaging. Vacuum packaging produced more exudate and a less bright red color than retail packaging. Coffi® had no significant effect on color or lipid oxidation by TBA. Objective measures of color and exudate quantity highly correlated with panel scores for the same parameters (r values of 0.91 and 0.95). TBA values were lower (P<0.05) in refrigerated vacuum-packaged than in retail-wrapped samples. The impact of vacuum on TBA was less apparent in frozen samples.     

辐照及贮藏条件对食品脂肪氧化影响的研究注

60Coγ射线辐照能加速食品脂肪氧化;辐照食品在贮藏的前期,其脂肪氧化速度与对照相比无明显区别,随着贮藏时间的延长,其脂肪氧化速度明显加快;不同辐照食品的脂肪氧化速度不同;贮藏温度对辐照食品脂肪氧化的影响较大,贮藏温度越高,脂肪氧化速度越快,但温度对不同辐照食品脂肪氧化的影响程度有所差别;抗氧化剂可明显地抑制辐照对食品脂肪氧化的影响和贮藏温度对辐照食品脂肪氧化的影响.     

辐照及贮藏条件对食品脂肪氧化影响的研究

^60Coγ射线辐照能加速食品脂肪氧化,辐照食品在贮藏的前期,其脂肪氧化速度与对照相比无明显区别,随着贮藏时间的延长,其脂肪氧化速度明显加快;不同辐照食品的脂肪氧化速度不同;贮藏温度对辐照食品脂肪氧化的影响较大,贮藏温度越高,脂肪氧化速度越快,但温度对不同辐照食品脂肪氧化的影响程度有所差别;抗氧化剂可明显地抑制吃一堑照对食品脂肪氧化的影响和贮藏温度对辐照食品脂肪氧化的影响。     

A Method for the Rapid Analysis of Headspace Volatiles of Raw and Roasted Peanuts

A rapid headspace analysis method for evaluating the flavor quality of peanuts using gas chromatography has been developed and tested. Samples are ground, heated in glass vials for 30 min at 150°C, and the headspace injected using a gas tight syringe. After initial startup, one can screen samples for flavor defects at the rate of four per hour. Of the peaks produced from peanut headspace analysis, most have been identified by gas chromatography/mass spectrometry and eight have been related to specific flavor characteristics.