Preserving sensory attributes of roasted peanuts using edible coatings

Peanut products are susceptible to develop rancid and off‐flavours through lipid oxidation. Preservation of these products is one of the problems in the peanut industry. The purpose of this work was to determine the sensory and chemical stability of roasted peanuts (RP) coated with different edible coatings: carboxymethyl cellulose (RP‐CMC), methyl cellulose (RP‐MC) or whey protein (RP‐WPI) during storage. Sensory attributes and chemical indicators (peroxide and p‐anisidine values, and conjugated dienes) of lipid oxidation were measured during storage. Chemical indicator values and intensity ratings of oxidised and cardboard flavours had lower increase in RP‐CMC, RP‐MC and RP‐WPI during storage than in RP, whereas roasted peanutty flavour showed a lower decrease. The stability of RP‐CMC is about a double longer with respect to RP. These results indicate that edible coatings preserve the sensory properties of roasted peanuts. Carboxymethyl cellulose exhibited the best protecting effect on this product.     

Effect of three lipid/hydrocolloid coatings on shelf life stability of Golden Delicious apples

The shelf life quality of freshly harvested Golden Delicious apples coated with three individually developed lipid/hydrocolloid coatings was assessed throughout refrigerated storage. The apples were monitored for 8 weeks. The coatings resulted in low internal O₂ and the least loss of fruit firmness when compared with the non‐coated apple group. The coated apples had very little starch breakdown, minimum flesh colour development, or loss of titratable acidity content. Soluble solids and fresh weight loss remained unchanged for both the non‐coated and coated groups. Sensory analysis confirmed that the coated apples maintained consistent quality in firmness, crispness and juiciness throughout the storage period.     

杏仁奶生产过程中稳定性控制的研究

杏仁奶是一种优质植物蛋白饮料,其营养价值可与牛奶媲美.但杏仁奶在生产过程中经常出现分离沉淀,酸败变质等问题,使杏仁奶的研制受到阻挠和困扰.阐明了各生产环节对杏仁奶稳定性的影响及处理的相应措施.     

Identifying drivers for consumer acceptance and purchase intent of corn tortilla

ABSTRACT:  The traditional production of corn tortilla has been modified by new processing technologies to make possible a commercial-scale production; this practice has resulted in products having sensory properties different from those produced by the traditional method. There is no published information on sensory attributes driving acceptance and purchase intent of corn tortillas. Identifying sensory drivers for acceptance and purchase intent of corn tortillas will help commercially produce products that satisfy consumers' expectations. A consumer study was conducted to evaluate acceptance and purchase intent of corn tortillas and determine drivers of acceptance and purchase intent of the products. Ten samples of corn tortillas were selected to represent a variety of corn tortillas available in the Mexican market. Three hundred Mexican consumers evaluated acceptability of appearance, color, thickness, rollability, resistance to tearing, aroma, chewiness, taste and aftertaste, and overall liking using a 9-point hedonic scale. Overall acceptance and purchase intent were determined with a yes/no scale. Analysis of variance and multivariate analysis of variance revealed that consumers were able to differentiate differences in sensory acceptability among 10 samples. For example, 2 homemade and 1 small commercial-scale samples, with an overall liking score of 6.6 to 6.7, were more acceptable than others. Rollability, resistance to tearing, and chewiness were attributes underlying overall differences among 10 samples. Attributes determining overall acceptance of corn tortillas were chewiness and overall liking. Purchase intent was influenced by overall appearance, rollability, chewiness, taste, and overall liking. This study revealed critical sensory attributes and their weights given by Mexican consumers when making decisions for acceptance and purchase intent of corn tortilla.     

Effect of macerate enzymes on the yield,quality, volatile compounds and rheological property of prickly pear juice

Pectinase and cellulase enzymes were used to investigate efficacy for improving juice yield, stability and quality from prickly pear fruit. Pectinase improved the yield, stable color, color‐assayed as release of anthocyanins or carotinoids and clarity of the juice. A significant increase in the effectiveness of pectinase was observed as the concentration was increased from 0.05 to 0.50% v/w. However, at concentration >0.25% v/w they tended to impart a bitter flavor in the juice. Among three concentrations of pectinase and cellulase, pectinase at 0.50% v/w produced higher yield, a sediment‐free clear juice and high‐quality juice. The results indicated that depectinated clarified prickly pear juice behaves as a Newtonian fluid. It was found that the activation energy (Ea) for viscous flow was in the range of 5.02×10³–20.06×10³ kJ/mol depending on the concentrations of pectinase and cellulase enzyme treatment of prickly pear juice, in contrast to 22.15×10³ kJ/mol in untreated juice. Volatile compound concentrations of twelve compounds were not affected by pectinase and cellulase treatment. Overall the quality of prickly pear juice was better in pectinase‐treated juice compared with untreated and cellulase‐treated juice.     

Ethanol production by fermentation of fruits and cladodes of prickly pear cactus [Opuntia ficus-indica (L.) Miller]

Using prickly pear cladodes and fruits and different yeast strains of the genus Saccharomyces, both the chemical composition of the plant material and alcoholic fermentation were studied under controlled conditions. Before fermentation, fresh or previously dried cladodes were hydrolysed using cellulose or acid (HCl). The yield was determined by measurement of ethanol production by gas-liquid chromatography. Two conversion indices, representing either the percentage of reducing sugars or the energy converted into ethanol, were considered. Using fresh or dried cladodes without fruits, the best results were always obtained after performing both types of hydrolysis. The enzymic method gave the highest sugar yield. However, ethanol production was similar to that obtained by acid hydrolysis of fresh cladodes, and only slightly higher than that of previously dried cladodes. The potential ethanol production that could be obtained from prickly pear cultivation in various regions (arid, semi-arid and irrigated) is discussed.     

Retail lighting and packaging influence consumer acceptance of fluid milk

Little is known about the effect of retail light-emitting diode (LED) exposure on consumer acceptance of milk. The study objective was to determine effects of fluorescent and LED lighting under retail storage conditions on consumer acceptance of milk. Consumer acceptance of milk stored under retail conditions was determined through sensory evaluation (2 studies; n = 150+ each) and analytical measures (dissolved oxygen, secondary oxidation products, riboflavin retention). Study 1 evaluated milk stored in high-density polyethylene (HDPE) packages for 4 h under LED light (960 lx). Commercially available HDPE package treatments included translucent HDPE (most commonly used), white HDPE [low concentration (1.3%) TiO₂], and yellow HDPE; in addition, HDPE with a higher TiO₂ concentration (high white; 4.9% TiO₂) and a foil-wrapped translucent HDPE (control) were tested. Translucent and control packages also were tested under fluorescent light. Study 2 evaluated polyethylene terephthalate (PET) packages for 4 h under fluorescent and LED light (1,460 lx). The PET packaging included 2 treatments (medium, 4.0% TiO₂; high, 6.6% TiO₂) as well as translucent HDPE (exposed to fluorescent), clear PET (fluorescent and LED), and light-protected control. Overall mean acceptability of milk ranged from “like slightly” to “like moderately” with significantly lower acceptability for milk exposed to fluorescent light. Milk in HDPE and PET packages had comparable overall acceptability scores when exposed to LED light. Only the fluorescent light condition (both PET and HDPE) diminished overall acceptability. Fluorescent light exposure negatively influenced flavor with significant penalty (2.0–2.5 integers) to overall acceptability of milk in translucent HDPE and clear PET. The LED also diminished aftertaste of milk packaged in translucent HDPE. Changes in dissolved oxygen content, as an indication of oxidation, supported the observed differences in consumer acceptance of milk stored under fluorescent and LED light. Consumers like the flavor of fresh milk, which can be protected by selecting appropriate packaging that blocks detrimental light wavelengths.     

Quality characteristics and consumer acceptance of yogurt fortified with date fiber

Yogurt is considered a healthy food and incorporating dietary fiber will make it even healthier. Date fiber (DF), a by-product of date syrup production, is a good source of dietary fiber. The effect of fortification with DF on fresh yogurt quality was investigated. Acidity, pH, color [L* (lightness), a* (redness), and b* (yellowness) values], texture profile, sensory properties, and consumer acceptance were studied. Control yogurt (without fiber), yogurt fortified with 1.5, 3.0, and 4.5% DF, and yogurt with 1.5% wheat bran (WB) were prepared. Fortification with DF did not cause significant changes in yogurt acidity, although pH was increased. Yogurts fortified with DF had firmer texture (higher hardness values) and darker color (lower L* and higher a*) compared with control or WB yogurts. Consumer test results indicated that the appearance, color, and flavor ratings were significantly affected by fiber fortification. Yogurt fortified with up to 3% DF had similar sourness, sweetness, firmness, smoothness, and overall acceptance ratings as the control yogurt. Sensory ratings and acceptability of yogurt decreased significantly when increasing DF to 4.5% or using 1.5% WB. Flavoring yogurt fortified with 4.5% DF with vanilla did not improve flavor or overall acceptance ratings. Thus, fortifying yogurt with 3% DF produced acceptable yogurt with beneficial health effects.     

咖啡杏仁乳的加工工艺及稳定性研究

以苦杏仁、咖啡为主要原料,研制一种复合型保健饮料。采用正交试验的方法确定合理的配方和适宜的工艺条件,并对产品质量作了评价。结果表明:杏仁量为3%、咖啡量为2%,加入6%的糖和0.4%的乳化稳定剂可以保证产品具有最佳的感官品质,同时具有稳定性好和滋味浓厚的特点。选择HLB为9.3为咖啡杏仁乳的最佳HLB值,即单甘酯与蔗糖酯的最佳比例为3∶7。在121℃下杀菌15min,制得的咖啡杏仁乳为咖啡色。35℃条件下进行保温7d,结果表明:咖啡杏仁乳在试验期内无沉淀,无脂肪分层,无变质腐败现象出现。     

Effect of whey protein isolate-pullulan edible coatings on the quality and shelf life of freshly roasted and freeze-dried Chinese chestnut

ABSTRACT:  Harvested chestnut is characterized by a short shelf life, exposing many Chinese producers to a storage problem as product losses are very high. The objective of this study was to develop a suitable technology to extend the shelf life of harvested chestnut fruits for commercial use. The effect of whey protein isolate–pullulan (WPI–Pul) coating on fresh-roasted chestnuts (FRC) and roasted freeze-dried chestnut (RFDC) quality and shelf life was studied under 2 different storage temperature (4 and 20 °C) conditions. Coatings were formed directly onto the surface of the fruits by dipping them into a film solution. SEM micrographs showed homogeneous WPI–Pul to cover the whole surface of chestnut with good adherence and perfect integrity. Moisture loss or gain, fruit quality, and shelf life were evaluated by weight loss or gain, surface color development, and visible decay during the storage period of 15 to 120 d at 4 and 20 °C, respectively. WPI–Pul coating had a low, yet significant effect on reducing moisture loss and decay incidence of FRC, hence delaying changes in their external color. The results were satisfactory when the coating was done with freeze-drying at low temperature storage, thus improving the quality and increasing the shelf life. This provides an alternative strategy to minimize the significant losses in harvested chestnut.     

增稠剂和乳化剂对豆浆稳定性的影响

为增加豆浆的稳定性,采用测定豆浆稳定系数、表面张力及进行感官评分的方法筛选适合用于豆浆样品的增稠剂和乳化剂,确定了最适宜的豆浆增稠剂和乳化剂的种类及其用量。经过黄原胶、刺槐豆胶、卡拉胶、结冷胶和海藻酸钠的单因素实验,黄原胶和刺槐豆胶的复配实验及黄原胶、刺槐豆胶和乳化剂(单硬脂酸甘油酯和蔗糖脂肪酸酯)的正交实验得出以下结果:黄原胶和刺槐豆胶对增加豆浆稳定性有着较好的效果,当它们的质量浓度分别为0.2g/L时,其稳定系数分别为0.737、0.742。单硬脂酸甘油酯和蔗糖脂肪酸酯复配后HLB=8、质量浓度为2g/L时,豆浆样品的稳定性最好,表面张力为41.7mN/m。当黄原胶、刺槐豆胶、乳化剂质量浓度(单硬脂酸甘油酯质量∶蔗糖脂肪酸酯质量=7∶4)分别为0.14、0.14、2g/L时豆浆的稳定性最好,此时豆浆样品的稳定系数为0.879,表面张力为41.6mN/m,感官评分为96。     

Oxidative stability and consumer acceptance of fish oil fortified nutrition bars

Oat and soy-based nutrition bars were fortified with 4 levels of fish oil (0, 6, 12, or 18 g per approximately 600 g batch), representing 0%, 20%, 40%, or 60% replacement of canola oil. The commercially available purified fish oil was not emulsified nor encapsulated, and contained tocopherols. Baked nutrition bars were evaluated for proximate composition, water activity, alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic (DHA) content, and consumer acceptance using a 9-point hedonic scale. The bars were sealed in opaque bags and stored in a stability chamber at 25 °C and 50% relative humidity for 10 wk to assess oxidative stability. There were no significant (P > 0.05) differences in proximate composition, water activity, or ALA levels among treatments. EPA and DHA levels were significantly (P < 0.05) different among treatments, averaging 178.1 mg/serving (20-FO), 488.3 mg/serving (40-FO), and 664.6 mg/serving (60-FO), but none changed during storage. Headspace hexanal and propanal levels decreased over time but were not significantly different among treatments until week 10. Peroxide values were not significantly different except between the control and 60-FO bars. Low values obtained for these analyses suggest negligible oxidation in the bars. Consumer acceptance scores did not differ significantly between the control and lowest fortification level (20-FO), ranging from 6.4 to 6.6 for aroma, texture, flavor, and overall acceptability. These results suggest that nonemulsified, nonencapsulated fish oil can successfully replace canola oil in intermediate moisture nutrition bars to provide EPA and DHA levels as high as 178 mg/serving without affecting consumer acceptability or oxidative stability. Practical Application: Omega-3 fatty acid rich fish oil has been shown to have numerous health benefits, but there are limitations to its use in shelf-stable food products. In this study, nutrition bars were successfully fortified with nonencapsulated, nonemulsified fish oil to deliver 178 mg EPA and DHA per 35 g serving. The fortified bars were oxidatively stable over 10 wk and acceptable to consumers.