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     

玫瑰和陈皮对烘炒花生仁货架期品质的影响

为探究玫瑰和陈皮对烘炒花生仁货架期品质的影响,以添加玫瑰花、陈皮的烘炒花生仁为研究对象,以添加0.2 g/kg 叔丁基对苯二酚（TBHQ）的花生仁、不额外添加的烘炒花生仁分别作为阳性和阴性对照,采用Schaal烘箱法对烘炒花生仁进行加速氧化,测定各组花生仁在烘箱储藏期间的酸价、过氧化值、丙二醛、色度、质构、水分含量、水分活度,并进行感官评价;采用风味值拟合一次函数,预测花生仁货架期。实验结果表明,与阴性对照组相比,添加植物组能较好地控制油脂水解、游离脂肪酸氧化程度,抑制氢过氧化合物和丙二醛值的上升,抑制花生L*值下降、a*值上升,丰富烘炒花生风味;与阳性对照组相比,添加植物组能较好地抑制丙二醛上升、维持花生色度。根据风味感官评分值拟合所得一次函数预测出货架期,陈皮组、玫瑰组、阳性对照组、阴性对照组的货架期分别为9.0个月、8.5个月、7.7个月和4.7个月。本实验为延长烘炒花生货架期提供了新的思路。     

Use of a spouted bed to improve the storage stability of wheat germ followed in paper and polyethlyene packages

Stabilization of wheat germ by heating in a spouted bed for 180–540 s with air at 140–200 °C was studied. The lipase activity decreased by 6–65%. Wheat germ processed at 200 °C for 360 s was ranked highest in sensory evaluation, described as having ‘a golden color’ and ‘nutty flavor’, and its lipoxygenase activity had decreased by 91.2%. This product and raw wheat germ were stored in paper, polyethylene and vacuum‐packed polyethylene pouches at 5 °C, room temperature (18–26 °C) and 40 °C, and the moisture contents, water activities, free fatty acid contents and peroxide values were followed for 20 weeks. The increases were faster in paper pouches than in the polyethylene ones; vacuum packaging in polyethylene did not bring about significant improvement. The peroxide values of raw samples exceeded 10 meq O₂ kg^?1 oil after 3–23 days while those of the processed samples stored at room temperature or 5 °C were still less than 10 after 20 weeks. The free fatty acid content and peroxide value changes were expressed by zero order kinetics, resulting in similar activation energies for the raw and processed samples. Copyright © 2005 Society of Chemical Industry     

Effect of Oxygen-Absorbing Packaging on the Shelf Life of a Liquid-Based Component of Military Operational Rations

ABSTRACT: Oxygen within the sealed package can reduce the quality of liquid‐based food products with high oil content such as hot‐filled meal‐ready‐to‐eat (MRE) cheese spread, a component of military operational rations. The aim of this study was to test a novel oxygen absorber‐containing laminate material and its ability to maintain and/or extend shelf life of a cheese‐spread MRE item. An iron‐based oxygen absorber (ABSO₂RB®) activated by moisture was incorporated into the laminate and used to pack hot‐filled cheese spread MREs. The kinetics of oxygen absorption due to humidity and temperature were characterized and peel tests performed to ensure pouch seal integrity. Accelerated shelf‐life tests of ABSO₂RB and regular MRE pouches without the O₂‐absorber were conducted for 3 mo at 51.7 °C (125 °F), and 6 mo at 37.8 °C (100 °F) by measuring oxygen concentration (Mocon O₂‐analyzer), microbiological, and physicochemical quality characteristics, including color, texture, moisture, free fatty acid (FFA), pH, water activity, and vitamins and A. Pouches stored at 26.7 °C (80 °F) for 12 mo served as calibrated controls. Consumer tests were conducted in‐house and a confirmatory sensory test was conducted at Natick by a trained panel using a 9‐point hedonic scale. ABSO₂RB‐laminates maintain the same seal integrity and strength as those of the control samples. The headspace oxygen concentrations in these pouches reached (P < 0.05) < 0.5% in 11 d of storage at 26.7 °C (80 °F) and remained below this level throughout the storage period (1 y). No microbial growth (aerobic, coliforms, yeast, and molds) was detected (P < 0.05) for both packages. Overall, the ABSO₂RB‐pouches indicate an improved reduction in oxygen and vitamin C retention compared with MRE controls and maintained product quality (physicochemical and organoleptic). ABSO₂RB‐laminates met the accelerated shelf‐life requirement of 1 mo at 51.7 °C (125 °F), and 6 mo at 37.8 °C (100 °F). This study clearly shows the benefits of using active packaging technology on retaining nutrition and prolonging shelf life of high‐fat, liquid content MRE items.     

Sensory changes in extruded oat stored under different packaging,light and temperature conditions

The sensory quality of extruded oat, stored in light and darkness in packages with different oxygen transmission rates (including the use of an oxygen absorber), was evaluated after 3 months of storage at 38 °C and 10 months of storage at 23 °C. To reduce the costly and time consuming shelf life and packaging evaluation, the possibility of reducing the number of sensory attributes to be analyzed and to accelerate shelf life testing was studied.The intensity of oat odor, paint odor and crispiness were found to describe the main differences among the samples. By increasing the temperature from 23 to 38 °C for samples stored in darkness, packaging evaluation tests for extruded oat might be performed in approximately one third of the time. Changes in headspace oxygen concentration in the packages due to oxygen consumption were in agreement with the sensory changes in the oat.     

Shelf-life of infrared dry-roasted almonds

Infrared heating was recently used to develop a more efficient roasting technology than traditional hot air roasting. Therefore, in this study, we evaluated the shelf-life of almonds roasted with three different approaches, namely infrared (IR), sequential infrared and hot air (SIRHA) and regular hot air (HA). Nine medium roasted almond samples produced by the aforementioned heating methods were processed at three different temperatures (130, 140 and 150 °C), packed in paper bags and then stored at 37 °C for three, six or eight months. Shelf-life of the roasted almonds was determined by measuring the changes in colour, peroxide value, moisture content, water activity, volatile components and sensory quality. No significant difference was observed in moisture content and water activity among the almond samples processed with different roasting methods and stored under the same conditions. GC/MS analysis showed that aldehydes, alcohols, and pyrazines were the main volatile components of almonds. Aliphatic aldehydes such as hexanal, (E)-2-octenal, and nonanal were produced as off-odours during storage. Although the overall quality of roasted almonds produced with SIRHA and HA heating was similar during the first three months of storage, their peroxide value and concentration of aliphatic aldehydes differed significantly for different roasting methods and increased significantly in all roasted samples during storage. We postulate that hexanal and nonanal might be better indicators of the shelf life of roasted almonds than the current standard, peroxide value.     

Effects of packaging materials,storage conditions and variety on oxidative stability of shelled walnuts

The effects of storage temperature, oxygen permeability of packaging material and variety on oxidative stability of vacuum-packaged walnut kernels were studied over a 12 months storage period. The oxidation experiments applied to two popular walnut varieties (Yalova-1 and Yalova-3) grown in Turkey. The peroxide values and hexanal contents of walnut samples significantly increased (p < 0.01) during storage at 30 °C. The highest hexanal content (4464.5–6406.9 μg/kg) were observed in Yalova-3 variety stored at 30 °C for 12 months in Polyamide/Polyethylene film pouches (oxygen permeability: 63.4 ± 0.4 mL/m²/24 h (23 °C)) with 90 μm total thickness. The effect of storage temperature and variety on lipid oxidation was found to be higher than the effect of oxygen permeability of the packaging material. It was concluded that for vacuum-packed walnut kernels in PA/PE film pouches having 63.4 ± 0.4 mL/m²/24 h (23 °C) oxygen permeability, 20 °C is sufficient to protect against oxidation for 12 months.     

Effect of oxygen absorber, nitrogen flushing, packaging material oxygen transmission rate and storage conditions on quality retention of raw whole unpeeled almond kernels (Prunus dulcis)

The present study investigated the effect of active packaging, nitrogen flushing, container oxygen barrier and storage conditions on quality retention of raw whole unpeeled almonds. Almond kernels were packaged in: a) polyethylene terephthalate//low-density polyethylene (PET//LDPE), and b) low-density polyethylene/ethylene vinyl alcohol/low-density polyethylene (LDPE/EVOH/LDPE) pouches under N_2, with or without an oxygen absorber, heat-sealed and stored for a period of 12 months. Quality parameters monitored were: peroxide value (PV), hexanal content, color, fatty acid composition and volatile compounds. PV ranged between 0.17 for fresh almonds and 9.22 meq O₂/kg oil for almonds packaged in PET//LDPE pouches under N₂ exposed to light at 20 °C after 12 months of storage. Respective values for hexanal were <28.5 μg/kg and 4.88 mg/kg. Polyunsaturated fatty acids (PUFA) and saturated fatty acids (SFA) increased with a parallel decrease of monounsaturated fatty acids (MFA) after 12 months of storage in all treatments. Likewise, volatile compounds such as aldehydes, ketones, alcohols, alkanes and aromatic hydrocarbons increased indicating enhanced lipid oxidation. Color was the parameter least affected. Use of the oxygen absorber provided a shelf life of at least 12 months for all samples irrespective of container oxygen barrier, lighting conditions and storage temperature.     

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     

炒货葵花籽的抗氧化效果研究

通过研究抗氧化剂、真空包装、充氮包装、添加脱氧剂等手段对葵花籽储藏过程中过氧化值的变化,探讨抑制炒货葵花籽氧化的方法。实验结果表明:炒货抗氧化剂的抗氧化性能优于BHT、BHA、茶多酚、竹叶异黄酮等单体抗氧化剂,并与其添加量呈正相关;添加抗氧化剂、真空包装、充氮包装、添加脱氧剂等方法均能抑制葵花籽过氧化值的升高,其抗氧化效果从大到小依次为:炒货抗氧化剂+脱氧剂>脱氧剂>炒货抗氧化剂>真空包装>充氮包装。采用炒货抗氧化剂结合脱氧剂抑制炒货葵花子的氧化效果最好,能将炒货葵花籽的保质期从2～3个月延长至10个月以上。     

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.     

澳洲坚果油脂肪酸组成及氧化稳定性分析

为了探究烘烤类澳洲坚果果仁的品质评价指标并建立品质评价体系,本文选取21种不同温度和时间烘烤的澳洲坚果果仁,对其进行了16项品质指标（褐变值、水分、总酚含量、ABTS⁺自由基清除率、酸价、过氧化值、硬度、破裂力、剪切力和7个感官评价项目）的测定和评价,并运用相关性分析、主成分分析和聚类分析的方法对16项指标进行分析,筛选出烘烤类澳洲坚果果仁品质评价的关键性指标。结果表明,随烘烤温度和时间的增加,澳洲坚果果仁水分、硬度、破裂力、剪切力以及感官评价的硬度均呈下降趋势,而褐变值、酸价、过氧化值、感官评价中的颜色、香气、香甜味、焦苦味、脆度、总体喜好度总体呈上升趋势,总酚含量和ABTS⁺自由基清除率呈先升高后下降的趋势;16项品质评价指标之间,11对指标之间有显著的相关性（P<0.05）,66对指标之间有极显著的相关性（P<0.01）,褐变值与感官评价中的颜色、香气、脆度、焦苦味呈极显著的正相关（P<0.01）,水分与硬度、破裂力、剪切力呈极显著的正相关（P<0.01）,总体喜好度与褐变值、总酚含量、ABTS⁺自由基清除率呈正相关,与硬度、破裂力、剪切力呈负相关,与感官评价中的颜色、香气、香甜味和脆度呈正相关;主成分分析表明130 ℃/30 min烘烤的澳洲坚果果仁综合得分最高;结合聚类分析,最终确定水分、褐变值、硬度、ABTS⁺自由基清除率、酸价和过氧化值6个指标为评价烘烤类澳洲坚果果仁品质的关键性指标。本文的研究结果为烘烤类澳洲坚果果仁的品质评价和研发加工提供了理论基础和科学依据。     

Effect of storage temperature and packaging on quality and shelf‐life of high pressure processed black tiger shrimp (Penaeus monodon)

The effect of high pressure processing (361 MPa/12 min/46 °C) on the quality and shelf‐life of black tiger shrimp was investigated. Changes in physical, biochemical, microbiological, and sensory attributes of samples packed in low density polyethylene (LDPE), ethylene vinyl alcohol (EVOH), and multilayer metalized polyester (MMP) pouches were examined during storage at 4, 15, and 25 °C for 30 days. The estimated shelf‐life of pressure treated samples based on sensory, chemical, and microbiological data was found to be 30 days for EVOH and MMP samples and 18 days for LDPE samples at 4 °C. The control and high pressure samples at 15 °C reach the unacceptable limit by 3rd and 9th day of storage, respectively. However, the samples at 25 °C showed shelf‐life of less than 3 days. Among the packages employed in the study, EVOH film was adjudged to be best in maintaining the quality of shrimp.

Practical applications

In global seafood market, shrimp is a commercially traded important commodity. The conducted study detailed about the quality changes occurred due to microbial activity and biochemical reactions in high pressure processed black tiger shrimp under different storage and packaging conditions and their impact on the shelf‐life. The provided data will be useful in the selection of appropriate conditions to preserve the valuable catch, establish high quality and safety requirements to enhance the marketing potential of shrimp.     

葵花籽不同包装方式储存品质的研究

对黑糖味瓜子的主要原料葵花籽进行研究,对熟制后的葵花籽进行6种不同方式包装,研究产品在食品储存期加速试验中的理化指标及感官变化情况。结果表明:熟制后搭配吸氧剂包装的葵花籽产品质量指标符合GB/T 22165与GB 19300标准要求。不同包装方式产品在0~4个月的加速试验期内,酸价值和过氧化值逐步增加,其中新纸袋未投放吸氧剂的产品在加速试验4个月中酸价值和过氧化值峰值为1.92mg KOH/g与0.811g/100g,储存效果最差;新纸袋加吸氧剂包装的产品酸价值和过氧化值最低,为1.47mg KOH/g与0.051g/100g,储存效果最好。     

Effects of storage conditions and cooking on colour and antioxidant activities of organic pigmented rice

Influences of the conditions of raw rice storage and cooking on parameters related to colour and antioxidant activities of organic hulled red fragrant rice were investigated. Raw rice samples were vacuum‐packed in oriented polypropylene/aluminium/linear low‐density polyethylene or nylon/linear low‐density polyethylene pouches and stored at ambient temperature or 15 °C up to 12 months. Cooked samples were prepared from aged raw samples. Kernel colour, total anthocyanin content (TAC) of acidic methanolic extracts as well as total phenolic content (TPC), reducing power (RP) and radical scavenging activity (RSA) of methanolic extracts and enzymatically digested samples were maintained during 12‐month storage, regardless of packaging materials and storage temperatures. Cooked kernels had larger L value, lower a and b values, and greater TAC (dry basis), comparing with the raw rice. Cooking caused drastic decrease in TPC, RP and RSA of methanolic extracts. Nevertheless, less negative impacts of cooking were found for enzymatically digested samples.     

Storage stability of jackfruit (Artocarpus heterophyllus) powder packaged in aluminium laminated polyethylene and metallized co-extruded biaxially oriented polypropylene during storage

Total colour difference (ΔE), rates of adsorbed moisture and sensory attributes of drum-dried jackfruit powder packaged in aluminium laminated polyethylene (ALP) and metallized co-extruded biaxially oriented polypropylene (BOPP/MCPP) pouches stored at accelerated storage (38 °C, with 50%, 75% and 90% relative humidity (RH)) were determined over 12 weeks period. The changes in total colour followed zero order reaction kinetics. Packaging materials, storage temperature and RH values significantly (p < 0.05) influenced the rates of adsorbed moisture of jackfruit powder. There was a significant (p < 0.05) decrease in the intensities of the fruity odour, taste and increase in the lumpiness of the jackfruit powder stored at 38 °C with 90% RH. The shelf life of jackfruit powder stored at 38 °C and 90% RH was limited by overall acceptability and the intensity of fruity odour, taste and lumpiness at week 8 of storage. Jackfruit powder stored at 28 °C remained stable and acceptable throughout the storage period for all RH values. The powder packaged in ALP significantly (p < 0.05) reduced total colour change, rates of adsorbed moisture, lumpiness intensity of jackfruit powder and was rated higher in terms of overall acceptability over BOPP/MCPP. Results of this study suggested that ALP packaging with storage conditions of 28 °C and RH less than 75% was better suited for keeping jackfruit powder.     

Storage study and quality evaluation of fresh coconut grating

This work is aimed at preservation of fresh coconut grating. Experiments were conducted to study effect of different storage temperatures (2.5, ?13.5 and ?20 °C) and salt concentrations (0, 0.5, 1 and 2% w/w) on microbial, sensory, physico‐chemical and structural characteristics of coconut grating, over one month storage. The relative extent of increase in total plate count, and yeast and mold count of grating significantly decreased with an increase in salt concentration at ?13.5 and ?20 °C. Coconut grating, with 2% salt, stored at ?13.5 °C indicated least increase in microbial count (2.69 to 4.20 log cfu/mL). Scanning electron microscopic images of samples indicated retention of microstructure during storage. Sensory analysis after one month at ?13.5 and ?20 °C, indicated higher overall acceptability, than at 2.5 °C. These samples were used for preparation of coconut chutney (eaten as an adjunct), which was found to be acceptable.

Practical application

Fresh coconut kernel grating is not shelf‐stable under ambient conditions due to high moisture and fat contents. This study gives an insight into the methods to improve the storage stability and quality of coconut grating under different conditions, using sensory evaluation, instrumental and microbial analysis. Fresh coconut grating with extended shelf life can meet the increasing demand as it finds application in various coconut based preparations.     

ACCELERATED STORAGE, SHELF LIFE AND COLOR OF MANGO POWDER

Vacuum‐dried mango powder was produced from mango pulp through the addition of glycerol monostearate and tricalcium phosphate at 0.015 kg each per kg mango solids and maltodextrin at 0.62 kg per kg dry mango solids. The mango powder was packed in aluminum foil‐laminated pouches and stored in an accelerated storage environment maintained at 90% relative humidity (RH) and 38 ± 2C. The sticky‐point moisture content at 38 ± 2C was considered as the maximum moisture content to which the mango powder would remain stable. The shelf life of the powder predicted from this consideration and the Guggenheim‐Anderson‐de Boer (GAB) model for the water activity moisture content relationship was 114.68 days, whereas the actual shelf life was 105 days. The color change of the powder during storage followed first‐order reaction kinetics with a rate constant of 0.038 per day.     

OXIDATIVE STABILITY OF SESAME PASTE (TEHINA)

Tehina samples were prepared from raw, roasted and steamed, or microwaved dehulled sesame seeds from Egypt. Samples contained 54, 96 α 0.36% lipid, 20.68 β 0.19% protein, 3.28 ± 0.05% ash and 1.76 ± 0.06% moisture. The peroxide values (PV) of tehina, stored under Schaal oven conditions at 65C after 35 days, reached 72.2, 86.2 and 97.2 meq/kg for samples prepared from raw, roasted and steamed, and microwaved seeds, respectively. The p-anisidine values (p-AnV) of samples stored under the same conditions and over the same period were 9.3, 10.1 and 10.2, respectively. Meanwhile, both PV and p-AnV of tehina samples stored at room temperature were considerably lower than those kept at 65 C and did not exceed 2.9 and 2.6 meq/kg, respectively. Both PV and p-AnV of tehina samples were lower than those obtained for oils extracted from dehulled sesame seeds which were subjected to similar pretreatment conditions.