Application of a mathematical model for chemical peeling of peaches (Prunus persica l.) variety Amarillo Jarillo

A previous model developed by the authors for chemical peeling of spherical foods was applied to peaches, which were assimilated to that geometry. Equations for the prediction of chemical peeling time as a function of temperature; alkali concentration and peeled thickness; and texture changes due to the cooking effect during peeling were established. Likewise, weight loss associated to peeling was determined. A total of 128 experiments were performed, involving caustic soda concentration of 1.6, 3.2, 5.6 and 7.3 (g/100 ml) and temperatures of 70, 80, 90 and 97 °C for peeling times from 0 to 8 min at 1-min intervals. Peeling maps to estimate peeling time for practical peeling conditions, including alkali temperature (70-97 °C), alkali concentration (1.6-7.3 g/100 ml), and peel thickness (0.02-0.05 cm) were developed.     

High-humidity hot air impingement blanching (HHAIB): An emerging technology for tomato peeling

Peeling is an essential operation for tomato processing. A new peeling method, high-humidity hot air impingement blanching (HHAIB) heating technology, was developed as an alternative to the conventional lye and hot-water peeling to eliminate the use of chemicals and the discharge of wastewater. The current work explored the feasibility of HHAIB for tomato peeling. The effects of heating temperature (100–120 °C), relative humidity (20%–40%) and heating time (0–180 s) on the peeling performance were investigated. The optimum treatment was found to be 110 °C heating temperature in combination with 40% of relative humidity and 75 s treatment time, which resulted in lower peeling loss, firmness loss and color deterioration compared with other HHAIB conditions that achieved 100% peelability. The comparative study of optimized HHAIB peeling with conventional lye and hot-water peeling showed that HHAIB peeled tomato obtained lower peeling loss and firmness loss, and higher preservation of phytochemicals, antioxidant capacity and color. In addition, compared with fresh tomatoes, HHAIB processing increased the antioxidant activity, lycopene, and total phenolic content in peeled tomatoes by 16.01%, 10.46%, 12.80%, respectively. The laser scanning confocal microscopy image of fresh tomato skin surface and the scanning electron microscope images of peels and flesh showed that HHAIB caused cracking of the epidermis and melting of the cuticular membrane while reduced the serious damage of flesh.Industrial practicePeeling is a necessary step in tomato processing, which impacts subsequent processing efficiency and product quality. At present, the most common used peeling methods in the industry are hot water or/and alkali peeling, but it induces the loss of water-soluble nutrients, chemical residues and waste liquid treatment. Therefore, the industry urgently needs an alternative peeling technology. The current work shows that HHAIB is a very promising peeling technology as it not only has an excellent peeling performance, but also enhances the preservation of phytochemicals, antioxidant capacity and quality attributes compared to conventional lye and hot-water peeling.     

USE of ORGANIC SOLVENTS FOR IMPROVING PEELABILITY of TOMATOES

A prepeeling dip was used to demonstrate that removal or modification of the cuticular waxes from the tomato fruit could be used to improve the tomato peeling process. the tomatoes were dipped at various temperatures for I min prior to regular lye peeling. the optimum temperature was found to be 45C. Several organic solvents including chloroform, ethyl acetate, ketones, and alcohols were used. These tomatoes were compared to tomatoes peeled using the lye without the dip. the prepeeling dip reduced the thickness of the cuticular wax layer and produced cracks in the cutin surface. This facilitated good penetration of lye into the tomato resulting in more complete peeling. Peeling after pretreatment produced 86% well peeled tomatoes as compared to 33% well peeled in the control run.     

Possibilities for application of laser ablation in food technologies

This work considers the possibility for using laser ablation in food technologies. It was found for the fruits and vegetables under study that laser ablation provided an efficient peeling of the materials while preserving the organoleptic properties, such as freshness, naturalness, and texture.After a laser treatment of citrus fruit (oranges and lemons), the fruits were peeled and pectin was extracted from the peels via a classical type of extraction in HCl water solution. The pectins obtained were assayed for yield, degree of esterification, polyuronic content, molecular weight, gel strength and other physico-chemical properties. For all samples it was found that laser pretreatment of the materials led to an increase in pectin yield, gel strength and purity, at an insignificant reduction of molecular weight and degree of esterification.Laser ablation of fruits and vegetables was used as an alternative to traditional methods for producing edible films. The cell particles, removed by means of laser ablation and containing plant waxes, cellulose fibers and pectic substances, were applied aseptically onto a hard surface and the obtained edible films showed a lasting antimicrobial effect.As a result of the treatment of fruits and vegetables with CO₂ laser, a number of aroma substances were released and they could be captured and used.

Industrial relevance

The work described in this research is relevant to the laser ablation of peeled fruit and vegetables used in food technologies. Laser treatment for peeling fruit and vegetables can be used not only by food processing enterprises, by catering companies and by fast food establishments as a preliminary treatment of fruit and vegetables, but also by pectin producers. There is also a prospect for the application of laser ablation in extracting aroma substances from various materials, as well as in obtaining edible films.     

猕猴桃无籽果羹加工工艺研究

以猕猴桃鲜果为原料,进行猕猴桃无籽果羹加工工艺与配方优化的研究,结果表明:以果实硬度大于9.0kg/cm2的鲜果经机械去皮、挖芯、破碎工艺制得的果泥47.2%,熟软果实榨汁得到的无籽果汁41.3%,复配稳定剂0.20%(0.08%卡拉胶+0.04%结冷胶+0.08%CMC),果葡糖浆11.2%的最优配方调配的猕猴桃无籽果羹产品,经常压90～95℃温度杀菌20min处理后保质期为6个月。     

PEELING OF YAMS FOR PROCESSING

White yam (Dioscorea rotundata) lye or flame peeled were evaluated for quality characteristics and peeling loss in comparison to hand peeling. Lye concentration (15–20% at 98°C with a dipping time 3–5 min) effectively removed the histological peel as the flame method, (flame temperature was 857°C and exposure time was 9 min) with a peeling loss of 4% which was significantly lower than for hand peeling. Fresh yams were more readily peeled by these methods than stored yams. The yams peeled by lye or flame when cooked were quite acceptable as hand peeled yams. The adaptability of these methods for industrial scale up are examined.     

不同去皮方法对番茄去皮效果和品质的影响

为优化现有番茄去皮工艺,开发新的去皮方法,以去皮难易程度和质量损失评价去皮效果,比较手工去皮、热水去皮、碱液去皮、功率超声去皮和超声与碱液联用去皮对去皮效果和产品质地、颜色、番茄红素提取率、p H值和可滴定酸含量等品质的影响,并结合扫描电子显微镜观察不同去皮方法果皮微观结构。结果表明,功率超声去皮较传统的热水去皮和碱液去皮,去皮难度小,质量损失少,且产品品质良好,番茄红素含量较高,而超声与碱液联用去皮较其他去皮方法虽去皮难度小,但质量损失过高。扫描电子显微镜观察结果表明,功率超声去皮较热水去皮、碱液去皮对果皮角质层的破坏力更大,可能是超声的空化效应使果皮与果肉更易分离,从而降低去皮损失。因此,功率超声去皮是一种潜在的新型环境友好型去皮方法。     

‘金艳’猕猴桃果实生长动态规律和贮藏性能

以‘金艳’猕猴桃果实为材料,通过持续测量田间果实的尺寸,检测田间生长和采后贮藏过程中的果实的品质,研究果实的生长动态规律和贮藏性能。结果表明:‘金艳’猕猴桃果实在谢花后7~175 d的发育过程中,果实尺寸(纵、横径)、单果质量和干物质含量都呈逐渐上升趋势;可溶性固形物含量前期增长缓慢,且波动较大,但在140~175 d期间,迅速上升;果肉颜色h0值在整个果实生长过程中逐渐下降。‘金艳’猕猴桃谢花后175 d左右进入采收期,当可溶性固形物含量在7.5%~8.0%范围时,适宜采收。‘金艳’猕猴桃耐贮性好,在0~1℃,相对湿度90%~95%的冷藏条件下,贮藏150 d,硬度下降到10.01 N/cm2。干旱会降低‘金艳’猕猴桃果实的单果质量和干物质含量,影响果实产量和品质。     

Alternative Method for Hazelnuts Peeling

The paper proposes an improved peeling treatment for hazelnut fruits consisting in dipping them in a solution (NaOH 0.4 g/100 g, NaH₂PO₄·H₂O 0.2 g/100 g) for 10 min at 50 °C, then scrubbing them with rubber rollers. The effects of the treatment on quality and peeling of four Italian hazelnut varieties were investigated. The data collected on peeling capability showed that the treatment proposed was effective in cuticle removal with a yield of peeling higher than 90%. The comparison of chemical–physical parameters in unpeeled and peeled hazelnut samples highlights that no difference was detected in texture, sugar, protein and α-tocopherol values. After the peeling process a significant change (p < 0.05) in colour, total fat and peroxide value was observed in peeled hazelnut samples when compared with the unpeeled ones. With regard to the sensorial parameters, no significant changes were found between unpeeled and peeled hazelnut samples. The peeling solution proposed in this study shows a good potential in industrial applications as an alternative to the usual manufacturing peeling method (roasting) that causes changes, not always desired, to some sensorial and chemical–physical parameters of the fresh fruit.     

PEELABILITY AND YIELD OF PROCESSING TOMATOES BY STEAM OR LYE

Approximately 25% of the processed tomatoes grown in California are made into value‐added foods such as whole peeled and diced tomatoes. Peel removal is the first step in this process, and it must be optimized for both quality and yield. The effect of peeling conditions on tomato cultivars Halley 3155 and Heinz 8892 (H 8892) was evaluated. Considerable texture loss results from peeling; however, firmness was greater for cv. Halley 3155 than for cv. H 8892 regardless of peeling conditions utilized. Peeling under low steam pressures (12 psig) was insufficient to adequately peel either cultivar. While high pressure steam (18 psig) was more efficient at peel removal, increasing vacuum level from 20 in. to 24 in. did not improve peelability of either cultivar. Because cultivar affected peelability and yield, specific tomato cultivars should be evaluated and directed to either paste or whole peeled and diced tomatoes as appropriate.     

酶膜分离法果汁澄清工艺

运用果胶酶，淀粉酶等澄清剂，结合膜分离技术，分析得出适合沙棘，柠檬汁，梨汁，猕猴桃汁，葡萄汁，梨汁，猕猴桃汁，葡萄汁，山渣汁，枣汁等果汁的澄清工艺。能有效去除果汁饮料中的果胶，蛋白和高级棕榈酸酯絮状物等造成沉淀的物质。     

DEFECTS AND PEELABILITY OF PROCESSING TOMATOES

Peeling is one of the first operations in the manufacture of whole peeled and diced tomatoes, and the peelability of processing tomatoes is significantly affected by the presence of various tomato defects, in particular yellow eye and blossom‐end rot. Tomato maturity also impacts both the percentage of peeled fruit and yield. Immature fruits are typically undercolored and small in size. Sunburned regions on the tomato surface are difficult to peel as well. In this study, we determined the impact of 24 selected tomato defects on tomato peelability and yield of whole peeled tomatoes. There are potential advantages to sorting to remove selected tomato defects early in the process.     

4种不同切割方式对鲜切莲藕品质和抗氧化性的影响

目的 分析比较4种不同切割方法处理莲藕在贮藏期间品质和抗氧化性的变化,筛选出最优的切割莲藕方式,为鲜切莲藕加工和贮藏提供理论基础。方法 以鄂莲5号莲藕为原料,采用去皮、切片、切丝以及切碎4种不同切割方式进行处理,分析菌落总数、色泽、呼吸强度、抗坏血酸、酚类物质、活性氧以及抗氧化酶等在贮藏期间的变化。结果 对比4种切割方式,去皮处理有效抑制菌落总数和失重率的增加,延缓鲜切莲藕褐变,更好维持莲藕的色泽。同时鲜切处理能够增强苯丙氨酸解氨酶和多酚氧化酶活性,诱导酚类物质含量积累,且随着切割损伤的越强而降低。去皮处理能够显著提高鲜切莲藕的总酚含量,其含量从140.46mg/kg增加到191.03mg/kg,增加率为36%,同时提高了1,1-二苯基-2-三硝基苯肼清除率和超氧化物歧化酶活性,提高率分别为84.01%和15.4%。结论 与切片、切丝和切碎处理相比,去皮处理能够显著抑制鲜切莲藕的褐变,同时诱导酚类物质含量增加,增强1,1-二苯基-2-三硝基苯肼清除率和超氧化物歧化酶活性,从而提高鲜切莲藕的抗氧化能力。     

Effects of heat treatment on atmospheric composition and color of peeled white asparagus in modified atmosphere packaging

Freshly harvested spears of white asparagus were subjected or not to heat treatment by immersion in a hot water bath at 55 °C for 3 min, then left unpeeled or were peeled before wrapping in 16 µm stretch film and stored at 3 °C for 6 days. During storage, the atmosphere within the packages was sampled for O₂, CO₂ and C₂H₄ determination, while spear fresh weight, color and anthocyanin content at the 3 cm apical peel segments were determined before and after storage. The results showed that CO₂ concentration in packages of white asparagus spears was not greatly influenced by peeling or heat treatment. On the other hand, a higher package O₂ depletion of treated (peeled or heated) spears was observed. Peeling also resulted in an increase of ethylene peak concentration, indicating wound-induced ethylene production, which was suppressed by heat treatment. The initial color of the whole spear was retained, while the appearance of a violet coloration on the spear tip was prevented by heat treatment in both unpeeled and peeled spears.Industrial relevancePeeled white asparagus has drawn the attention of industry as a novel lightly processed product. The combination of heat treatment with modified atmosphere packaging (MAP) could be used to improve the storage life of this product. Moreover, both peeling and heat treatment cause changes in ethylene production and respiration rate of asparagus spears and this information could be useful for development of novel application to MAP design for lightly processed (peeled) white asparagus.     

RELATIONSHIP OF TREATMENT OF FRESH STRAWBERRIES TO THE QUALITY OF FROZEN FRUIT AND PRESERVES1

‘Cardinal’ strawberries were hand picked and stored 1 day at 21°C to enhance softening. Three separate preprocessing experiments were conducted to determine the effects of style of pack, 0.18% calcium (Ca) dips, 0.3% low methoxyl pectin (LMP), 40° Brix sucrose dips, heat of 70°C, vacuum at 172 mm Hg and drying to 70% moisture on quality and firmness of frozen-then-thawed and preserved strawberries. The greatest firming effect on frozen-then-thawed fruit was due to Ca and pectin. Sliced fruit was firmed more than whole fruit by the Ca and pectin treatments. Drained weight loss was reduced by pectin, Ca, sucrose, heat and vacuum in frozen-then-thawed fruit. Drained weight losses were the same or greater among treatments in preserves. The firmness and wholeness of preserves was increased by Ca, vacuum, 40° Brix sucrose, heat and to a lesser extent drying, but individual effects were not additive. The drying treatment reduced color quality.     

猕猴桃碱法去皮工艺参数和效果的决策预报

以陕西中华猕猴桃为植物材料,研究了碱法去皮中NaOH浓度、作用时间和温度三个工艺参数的不同组合对去皮后果实生理指标和效果的影响,结果表明,硬度、可溶性固形物、还原糖、蔗糖、总糖、单宁和总酸的含量均下降,其中以含糖量下降最大。三参数中以NaOH浓度对去皮效果以及果实理化性质的影响最大,其回归方程可预报去皮后果实理化以及感官指标;硬度与各项理化以及感官指标的相关性最好,可作为去皮效果的快速诊断因子。     

几种主要产地猕猴桃的果籽营养成分比较

对湘西野生猕猴桃、湘西米良1号猕猴桃、陕西秦美猕猴桃、贵州中华猕猴桃的果籽含量及其营养成分进行分析对比。结果表明：湘西米良1号猕猴桃果籽含量及其粗脂肪、亚麻酸、微量元素硒含量均高于其它产地，但亚油酸含量低于其它产地；不同产地猕猴桃果籽Vc与氨基酸含量差别不大，贵州中华猕猴桃果籽VE最高。     

RELATIONSHIP BETWEEN THE TEXTURE AND PECTIN CONSTITUENTS OF JAPANESE PEAR

The relationship between texture and pectin constituents and some related compounds of the Japanese pear (Pyrus serotina Render var. culta 'Housui') during fruit enlargement and ripening was studied. The modulus of elasticity, deformation ratio, and relaxation value from the flat plate compression test, and all the properties from the puncture test were affected by the pectin constituents, alcohol insoluble solids, and soluble solids. The hardness and deformation of the fruit obtained from the plate compression test might depend on the combination of the alcohol insoluble solids in fresh weight and weight of the fruit. The oxalate soluble pectin both in alcohol insoluble solids and in fresh weight affected the fruit texture more than the water soluble pectin. The solubitization of nonsoluble pectin to water soluble pectin appeared to influence the textural properties more than that of the nonsoluble pectin to oxalate soluble pectin. The puncture test was superior in analyzing the textural properties of the Japanese pear fruits with regard to changes in the pectin constituents.     

3种脱皮方式对白胡椒品质的影响

以胡椒鲜果为原料,分别采用机械、静水浸泡、换水浸泡3种方式脱皮,探究不同脱皮方式对白胡椒白度值、黑果率、碎果率、堆积密度、水分质量分数、胡椒碱含量、胡椒精油含量等理化指标的影响,利用气相色谱-飞行时间质谱（gas chromatography-time of flight-mass spectrometer,GC-TOF-MS）定性定量分析测定胡椒精油的成分及含量,采用加权分析法进一步评价3种脱皮方式所得白胡椒品质。结果表明：机械脱皮与换水浸泡脱皮生产的白胡椒白度值无显著差异,但高于静水浸泡脱皮法生产的白胡椒。机械脱皮法生产的白胡椒黑果率、胡椒碱含量低于静水、换水浸泡脱皮法生产的白胡椒,但精油含量、碎果率、堆积密度高于后两者。从机械、静水浸泡、换水浸泡脱皮生产的白胡椒精油中共鉴定出33种化合物,其中21种为3种白胡椒精油共有,质量浓度较高的共有化合物有3-蒈烯（41.96、37.77、39.16 mg/mL）、β-石竹烯（36.43、41.57、41.02 mg/mL）、柠檬烯（29.38、23.38、39.38 mg/mL）等。电子鼻分析结果表明3种白胡椒风味差异显著。感官评价证实机...     

Effect of Steam Temperature, Speed of Cooling and Cutin Disruption in Steam and Lye Peeling of Apples

A laboratory model steam peeler was adapted to accept superheated steam and direct injection of cold water in order to study the effect of rapid heating with superheated steam and rapid cooling under partial vacuum on the peeling efficiency of‘Red Delicious’apples. A test was also designed to determine the effect of physical disruption of the cutin layer on the efficiency of caustic peeling. Steam peeling resulted in higher peeled yields and brighter product color than caustic peeling. The peeled yields were 97.5% for superheated steam-peeled apples with flash cooling, 91.7% for caustic peeled fruit which had a prepeel treatment to physically disrupt the cutin layer, 85.8% for conventionally caustic-peeled fruit, and 82.7% for the mechanically peeled control.