Irradiation and Packaging Affect the Nitrate-Nitrogen Concentrations of Potatoes

Russet Burbank and Kennebec potato cultivars were irradiated with dosages of 0.1 and 1.0 KGy and stored in polyethylene or paper bags for 1 or 3 mo at 5°C or 20°C. Tubers receiving irradiation showed a significant (p<0.01) increase in nitrate-nitrogen concentration as compared to controls. Those receiving the 1.0 KGy dose had the highest nitrate-nitrogen concentration. Tubers stored in polyethylene bags were significantly (p<0.01) higher in nitrate-nitrogen concentration than those stored in paper bags. Tubers stored at 20°C were significantly (p<0.01) higher in nitrate-nitrogen than those stored at 5°C. These trends were consistent for both cultivars. The cortex region was significantly (p<0.01) higher in nitrate-nitrogen concentration than the pith region. Kennebec tubers were significantly (p<0.01) higher in nitrate-nitrogen than the Russet Burbank tubers for all irradiation doses and storage temperatures.     

Effect of storage on chemical and sensory profiles of peanut pastes prepared with high‐oleic and normal peanuts

BACKGROUND: Peanut paste and peanut butter have high oil contents and are thus susceptible to developing rancidity and off‐flavours through lipid oxidation. Preservation of the chemical and sensory quality of these products is one of the main problems in the peanut industry. The purpose of this study was to compare the chemical and sensory stability of peanut paste prepared with high‐oleic peanuts (cv. Granoleico, GO‐P) with that of peanut paste prepared with normal peanuts (cv. Tegua, T‐P) from Argentina. RESULTS: Chemical (peroxide and p‐anisidine values and conjugated dienes) and sensory (roasted peanutty, oxidised and cardboard flavours) indicators of lipid oxidation were measured in peanut pastes stored at 4, 23 and 40 °C. Chemical indicator values and oxidised and cardboard flavours showed lower increments in GO‐P than in T‐P during storage. T‐P had significantly higher peroxide value than GO‐P. Roasted peanutty flavour showed a lower decrease in GO‐P. Peanut paste prepared with high‐oleic peanuts had four (at 4 °C), two (at 23 °C) and three (at 40 °C) times longer shelf‐life than peanut paste prepared with normal peanuts. CONCLUSION: These results indicate that high‐oleic Granoleico kernels provide peanut paste with higher protection against lipid oxidation. Copyright © 2010 Society of Chemical Industry     

Effects of oil roasting temperature and time on the quality of two Macadamia integrifolia cultivars

The effects of oil roasting temperature and time on the quality of kernels from two Macadamia integrifolia cultivars, were determined. A high quality product was obtained by roasting at 115°C for 19–35 min, 125°C for 10–14 min or 135°C for 4 min. There was a significant deterioration in the quality of nuts from all roasting treatments when stored for 6 months at ambient temperature in lacquered cans at a pressure of ?85 kPa. Further deterioration had occurred after 12 months storage.     

Production of Peanut Flour from Microwave Vacuum-Dried Peanuts

Defatted peanut flours with significantly reduced raw peanut taste and nitrogen solubility of 85+% were produced from field Runner peanuts that had been microwave-vacuum-dried to maximum temperatures of 80°C and 96°C. The flours were prepared from 4.54 kg of peanuts, dried from 25.5% to less than 10% moisture, at 375 Torr absolute pressure and at 1400 and 813 watts microwave power (2450 MHZ). Peanut temperature at end of drying significantly affected the intensity of the raw peanut flavor. Storage at 23.9°C for 14 months had no significant effects on intensity of the raw peanut flavor. Hexane extraction of blanched peanut kernels showed that mass velocity percolation rates increased with increase in final drying temperature of peanuts.     

Property Characterization of Peanut Kernels Subjected to Gamma Irradiation and Its Effect on the Outgrowth and Aflatoxin Production by Aspergillus parasiticus

Peanut kernels inoculated with Aspergillus parasiticus conidia and uninoculated kernels were gamma irradiated with 0 to 15 kGy using ⁶⁰Co. Levels of 2.5 and 5.0 KGy were effective in retarding the outgrowth of A. parasiticus and reducing the population of natural mold contaminants. However, elimination of these molds was not achieved. When irradiated with doses higher than 10 KGy, seed germinations were inhibited, changes in proteins were observed and oil stabilities decreased. After 4 wk incubation of the inoculated kernels in a humidified condition, aflatoxins produced by surviving A. parasiticus ranged from 69.12 to 13.48 μg/g depending upon the original irradiation dose.     

Effects of gamma irradiation dose and short-term storage on phytochemicals,antioxidants, and textural properties of boiled ‘Tainan 9’ peanuts

Boiled peanuts are preferable as a ready-to-eat healthy snack; however, gamma irradiation as a postharvest treatment of raw peanuts may induce unfavourable food components. Hence, the phytochemical, antioxidant, and the texture of boiled ‘Tainan 9’ peanuts pretreated with gamma irradiation (0, 2.5, 5, and 10 kGy) and stored at 29 ± 2 °C for up to 180 days were investigated. Both gamma irradiation and storage time contributed to testa darkening in raw peanuts. In boiled irradiated products, irradiation doses and storage time affected the moisture content (MC), total proteins, total oil, total soluble sugars, and antioxidant capacity (P ≤ 0.05). Total phenolic and flavonoid contents showed an increase at days 90 and decreased at days 180 across all treatments. A positive correlation was observed among ferric reducing antioxidant power (FRAP), total phenolics, and total flavonoids. Gamma irradiation at 10 kGy led to increase of peroxide value (PV) (P ≤ 0.05), but malondialdehyde (MDA) content was unaffected. Textural properties of boiled irradiated peanuts were soft. As a result, gamma irradiation at 5 kGy is recommended for postharvest treatment of raw peanuts with subsequent storage up to 180 days to obtain the eating quality of boiled peanuts with good phytochemicals and antioxidant properties, which is a challenge for food industry.     

Effects of gamma irradiation and storage temperature on carotenoids and ascorbic acid content of mangoes on ripening

Synthesis and accumulation of carotenoids in the flesh of Alphonso mangoes on ripening was found to be maximal in fruits stored at tropical ambient temperatures (28–32°C). Gamma irradiation of preclimacteric fruits at 25 krad did not affect the formation of carotenoids. Storage of preclimacteric fruits either irradiated or unirradiated at 7–20°C for 16–43 days caused a substantial reduction in carotenoid formation even when these fruits were subsequently ripened under optimal conditions. Regardless of storage temperature, carotenes always exceeded xanthophylls in the ripe fruits and, in general, irradiated fruits showed higher levels of carotenes in comparison with unirradiated samples. Ascorbic acid loss during ripening was maximum at ambient temperatures while lengthy storage at low temperatures caused a net increase in ascorbic acid levels. Irradiation seemed to accentuate the loss in ascorbic acid during ripening.     

Effect of irradiation, active and modified atmosphere packaging, container oxygen barrier and storage conditions on the physicochemical and sensory properties of raw unpeeled almond kernels (Prunus dulcis)

BACKGROUND: The present study investigated the effect of irradiation, active and modified atmosphere packaging, and storage conditions on quality retention of raw, whole, unpeeled almonds. Almond kernels were packaged in barrier and high‐barrier pouches, under N₂ or with an O₂ absorber and stored either under fluorescent lighting or in the dark at 20 °C for 12 months. Quality parameters monitored were peroxide value, hexanal content, colour, fatty acid composition and volatile compounds. Of the sensory attributes colour, texture, odour and taste were evaluated. RESULTS: Peroxide value and hexanal increased with dose of irradiation and storage time. Irradiation resulted in a decrease of polyunsaturated and monounsaturated fatty acids during storage with a parallel increase of saturated fatty acids. Volatile compounds were not affected by irradiation but increased with storage time indicating enhanced lipid oxidation. Colour parameters of samples remained unaffected immediately after irradiation. For samples packaged under a N₂, atmosphere L* and b* values decreased during storage with a parallel increase of value a* resulting to gradual product darkening especially in irradiated samples. CONCLUSION: Non‐irradiated almonds retained acceptable quality for ca. 12 months stored at 20 °C with the O₂ absorber irrespective of lighting conditions and packaging material oxygen barrier. The respective shelf life for samples irradiated at 1.0 kGy was 12 months packaged in PET‐SiOx//LDPE irrespective of lighting conditions and 12 months for samples irradiated at 3 kGy packaged in PET‐SiOx//LDPE stored in the dark. Copyright © 2010 Society of Chemical Industry     

Polyphenolic and antioxidant changes during storage of normal,mid, and high oleic acid peanuts

The quality of dry roasted peanuts is highly dependent on storage conditions for preventing oxidation of fatty acids; however, changes in polyphenolics affecting antioxidant capacity due to co-oxidative reactions are unknown. The objective of this work was to evaluate oxidative stability of polyphenolics in peanut kernels with naturally varying rates of lipid oxidation. Three peanut varieties containing varying levels of oleic acid (normal, mid, and high) were dry roasted and evaluated for phytochemical changes over four months of storage at 20 and 35 °C; analyses included peroxide value, total and individual phenolics and antioxidant capacity. The normal oleic acid peanuts suffered up to 2.6-fold and mid-oleic acid peanuts 2-fold more lipid oxidation than the high-oleic acid peanuts stored at 35 °C. Changes in total soluble phenolics were initially similar among cultivars, but antioxidant capacity was found to decrease by 62%, on average, during storage at 35 °C, independently of rates of lipid oxidation. Free p-coumaric acid, three esterified derivatives of p-coumaric, and two esterified derivatives of hydroxybenzoic acid were the predominant polyphenolics present and their rates of change were similar among cultivars and independent of storage time or temperature. The high-oleic acid content was essential for prevention of lipid oxidation, but data indicated that co-oxidative reactions, affecting polyphenolic content during storage, were not great enough to significantly alter antioxidant capacity.     

Vitamin A in irradiated foodstuffs (author's transl)]

Vitamin A losses induced by 10 MeV electrons in cream cheese, calf liver sausage, pig liver, whole egg powder and margarine continued to increase during storage for 4--8 weeks in presence of air. Thus vitamin A loss in sausage irradiated with 5 Mrad was 22% on the day after irradiation, 61% after 4 weeks. Irradiation and storage at 0 degrees C instead of at ambient temperature reduced these losses considerably. Exclusion of air (vacuum, nitrogen) or irradiation on dry ice (approx. -80 degrees C) were even more effective in preventing destruction of vitamin A. After 4 weeks of storage, cream cheese irradiated at 5 Mrad had lost 60% when irradiated and stored in air at ambient temperature, 20% in nitrogen atmosphere, 5% in vacuum package, and 5% when irradiated on dry ice and stored at ambient temperature.     

Eigenschaften der Stärke aus den gammabestrahlten und bei verschiedenen Temperaturen gelagerten Kartoffelknollen

The Properties of Starch Obtained from Irradiated and at Various Temperatures Stored Potato Tubers. Potato tubers were either exposed to gamma irradiation (150 Gy) or not. They were stored at temperatures of +4°C, +7°C and +13°C for six months. The properties of the starch obtained from the irradiated tubers after storage were different from the starch obtained from the tubers before storage and from the starch obtained from the tubers not exposed to gamma irradiation. Range and trends of changes in starch properties depended on the temperature of storage.     

The effects of stabilised extracts of sage and oregano on the oxidation of salad dressings

The antioxidative activity of sage and oregano either dissolved in ethanol or homogenised with olive oil as a carrier was evaluated in salad dressings. These samples were stored in the dark at ambient temperature and at 40 °C, and with light exposure at ambient temperature. Sage and oregano extracts were encapsulated in liposomes by ultrasonification or microfluidisation, and their structures confirmed by microscopic examination and dye-marker carboxyfluorescein. The antioxidant effect of these preparations was evaluated in salad dressings during storage in the dark at ambient temperature, at 40 °C and at 60 °C. The oxidation process was followed by measuring the formation of conjugated diene hydroperoxides as primary and hexanal as secondary oxidation products, as well as changes in the compositions of fatty acids and tocopherols. Oregano and sage extracts homogenised with olive oil as a carrier showed higher antioxidative effects than these extracts dissolved in ethanol during storage in the dark at ambient temperature and at 40 °C. Exposure of salad dressings to light changed the antioxidative effect of plant extracts into a pro-oxidative effect. The preparation of liposomes by microfluidisation showed higher encapsulation efficiency and more homogeneous vesicles than liposomes prepared by ultrasonification. Sage liposomes prepared by micofluidisation showed high antioxidative effects similar to butylated hydroxytoluene liposomes in salad dressings during storage in the dark at ambient temperature and at 40 °C.     

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.     

Quality of Gamma Irradiated California Valencia Oranges

California Valencia oranges were irradiated at 0.30, 0.50, 0.75 and 1.0 kGy for quality evaluation and potential use of gamma-radiation as an alternative quarantine treatment and for fresh market life extension. Fruits were ocean-freighted to Honolulu, irradiated at the Hawaii Research irradiator 8 days after harvest, then stored for 7 wk at 7°C or 4 wk at 7°C and 2 wk at 21°C (6 wk total). Treatments of 0.75 kGy maintained fruit qualities at low storage temperature (7°C) up to 7 wk while 0.50 kGy retained qualities when fruits were stored at 21°C. Gamma irradiation of Valencia oranges at 0.26–0.30 kGy can achieve fruit fly disinfestation at probit 9 security level while preserving market qualities including organoleptic qualities, ascorbic acid, total acids, and total soluble solids.     

THE STORAGE OF PELLETED POWDERS MADE FROM WYE NORTHDOWN HOPS

Pelleted hop powder from seeded Wye Northdown hops of the 1976 crop shows small losses in lead conductance value (LCV) when stored in commercial packs for ca. 12 months after processing. The losses for hop pellets stored at ambient temperature are slightly more rapid than for those stored at 0 to 4°C. Losses in LCV of pellets during storage in the cold or at ambient temperature are substantially less than those of seeded Wye Northdown cone hops stored in pockets under comparable conditions. The hop pellets showed no significant loss in oil content or bittering potential over the storage period. Taste panels were unable to detect differences in flavour when comparisons were made of beers bittered with pellets stored in the cold and at ambient temperature.     

储藏条件对花生的氨基酸和脂肪酸组成及风味的变化影响

花生在储藏过程中易走油霉变,分析花生在贮藏过程中的氨基酸和脂肪酸含量变化是研究花生品质的重要内容。将花生在低温常湿、常温低湿和常温常湿环境下储藏12个月,利用高效液相色谱和气相质谱联用仪测定不同储藏条件下花生的氨基酸与脂肪酸随储藏时间的变化情况,结合电子鼻和傅里叶变换红外吸收光谱对花生品质进行分析。研究结果显示:低温冷藏环境下花生中氨基酸总量由233.42 mg/g降至215.41 mg/g,常温常湿的条件下降至197.85 mg/g;脂肪酸变化最明显的是油酸和亚油酸的含量,低温冷藏12个月后O/L值从0.94上升至0.96,而常温低湿条件下达到1.54,亚油酸遭到严重破坏;红外谱图中蛋白质和脂肪酸的特征峰1653 cm^-1和1744 cm^-1均减弱,常温常湿条件下最明显。低温冷藏是最佳贮藏条件。      

Effect of harvest time and storage conditions on almond kernel oil and sugar composition

The effect of storage for 6 months at 5 °C (80% RH) versus 20 °C (60% RH) of shelled versus in‐shell almonds was studied on early versus late harvested nuts from ‘Ferragnes’ and ‘Texas’ trees. Kernel quality characteristics, oil composition and sugar composition were determined initially and after 6 months of storage. Early harvested almonds had similar kernel weight to but higher moisture content than late harvested almonds after 6 months of storage. Early harvested almonds also had similar oil quality (based on ultraviolet absorption coefficient measurements) and oil composition but lower sugar content and modified sugar composition compared with late harvested almonds. Storage of shelled almonds resulted in kernels with higher oil content, better oil quality, similar oil composition, similar sugar content and some modifications in sugar composition compared with in‐shell stored almonds. Finally, storage for 6 months at either 5 or 20 °C resulted in lower moisture content, higher oil content, similar oil quality and composition, similar sugar content and some modifications in sugar composition compared with freshly harvested almonds. Almonds stored at 5 °C retained higher kernel weight and moisture content than almonds stored at 20 °C. © 2003 Society of Chemical Industry     

Shelf Life of Sunflower Kernels

One raw and two oil roasted samples of sunflower kernels packaged in paper bags and in two types of low oxygen atmosphere pouches were stored at 5, 21 and 38°C. Quality of the stored samples was monitored by an expert sensory panel, peroxide, hexanal, free fatty acids and moisture determinations. Liking ratings, obtained with 99 consumers after 24 wk storage, were used to select end points for expert sensory ratings. The shelf life for roasted sunflower kernels was greater than 12 month when stored in nitrogen flushed pouches and as low as 8 wks when exposed to air at 38°C. Hexanal was a better index for shelf life of roasted sunflower kernels than was peroxide. The shelf life of raw sunflower kernels was > 12 month in packages providing some moisture but no oxygen protection.     

Composition, stability and acceptability of different vegetable oils used for frying peanuts

The purpose of this work was to determine the chemical stability of vegetable oils in the frying process and the consumer acceptance of fried-salted peanuts prepared in different vegetable oils. Fatty acids composition was determined in sunflower, corn, soybean, peanut and olive oils. A chemical study (free fatty acid and p-anisidine values) of these oils at frying temperature (170 °C) was developed during 96 h. Consumer test of fresh products was performed on fried-salted peanuts prepared in the different oils. Peanut oil and virgin olive oil presented oleic acid as predominant fatty acid (44.8% and 64.2%, respectively), making it more resistant to lipid oxidation at frying temperature than the other refined vegetable oils (sunflower, corn and soybean oils). Virgin olive and peanut oils showed less increment of free fatty acids and p-anisidine value than the other oils along the heating essay. In addition, fried-salted peanuts prepared with refined peanut oil showed higher consumer acceptance than those prepared with other vegetable oils such as sunflower, corn, soybean and olive oils. Peanut oil could be used to fry peanuts obtaining products with higher consumer acceptance and shelf-life, thus preventing loss of their sensory and nutritional quality.     

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.