功率超声对番茄去皮的影响

传统的番茄去皮方法为碱液去皮和热力去皮,碱液去皮易造成环境污染,热力去皮质量损失高。为开发新的去皮方法,以去皮难易程度和质量损失评价去皮效果,以产品硬度、颜色、番茄红素含量、pH值和可滴定酸含量评价产品质量,研究番茄功率超声去皮中,超声时间、超声功率和超声温度对去皮效果和产品质量的影响。研究结果表明,在40 kHz,270 W/L,95°C超声60 s,去皮容易,去皮质量损失低(8.18%),去皮番茄颜色佳(L*=36.94,a*=28.95,b*=19.00),番茄红素含量高(33.48 mg/kg),硬度保持好(1.59 N),pH值(4.18)和可滴定酸含量(0.70%)无显著影响,能取得较好的去皮效果和产品质量。功率超声去皮消除了碱液的应用,降低了质量损失,是一种新型的环境友好型去皮方法。     

基于催化式红外的西红柿干法去皮技术

目的：探寻一种高效且绿色环保的西红柿去皮方法。方法：利用催化式红外设备进行西红柿干法去皮，考察工艺参数对西红柿去皮性能和果肉品质的影响，并与传统的热水和碱液去皮方式进行对比。结果：双板距离、红外加热温度和红外加热时间均对西红柿去皮率和果肉品质有显著影响（P<0.05），西红柿催化式红外干法去皮的最优工艺参数为催化红外温度450 ℃，双板距离25 cm，红外处理时间5 min，此时西红柿去皮率高达98%，且果肉硬度（7.60 g/mm²）和番茄红素含量（30.39 mg/kg）最优，颜色鲜红。与传统热水和碱液去皮方式相比，红外去皮属于干法去皮，是一种环境友好型的去皮方法；红外去皮处理后西红柿果肉具有最高的硬度、番茄红素含量，颜色更红润，果肉完整性良好；红外去皮处理对果皮和果肉微观结构的影响最小，对果皮果肉连接层的微观结构有明显影响，促进了果皮与果肉的分离，表明红外去皮机制与其他几种去皮方式不同。结论：催化式红外去皮方式更适合西红柿的去皮加工，可以实现高效去皮、绿色环保且能保障产品品质。     

核桃仁去皮工艺的研究

通过不同碱液处理和烘烤方法对核桃仁去皮工艺进行了研究,结果表明,以4%Na2CO3和10?OH2混合液95℃热烫3min去皮效果最好,去皮率达83.09%,且核桃仁色泽良好,质地脆硬。     

核桃仁碱液去皮过程中营养功能成分动态变化

对碱液去皮前后核桃仁营养功能成分的流向进行了跟踪分析.结果表明:碱液去皮后,核桃仁的水分含量增加了16.84％,粗蛋白、粗脂肪含量分别减少了24.7％、4.1％;必需氨基酸评分(AAS)从1.82降低到1.28;核桃仁内种皮总酚和总黄酮含量分别下降81.7％和72.2％;核桃仁蛋白的溶解性也明显降低.去皮核桃仁在后续烘干过程中颜色变成暗黄色,且核桃仁油的酸值(KOH)和过氧化值增加(分别增加0.43 mg/g、1.78 mmol/kg).碱液去皮工艺废水COD为17500～21100 mg/L,远远超过了国家二级污水排放标准.碱液去皮工艺还存在许多不足之处.     

核桃仁去皮方法的研究

因为核桃仁外有一层种皮，它含有色素和苦涩味等成分，会严重影响产品质量，所以必须将它去除，在给核桃仁去皮时可分为两种方法：第1种，可采用碱液浸泡去皮法进行脱皮；第2种，加热煮沸法，可直接放入蒸馏水中加热至沸腾，闷制一定时间后取出，手工进行去皮。通过比较，碱液法去皮会使核仁的颜色有所变化，核仁品质降低；加热煮沸法效果较好，可较好地的保障了核仁的品质。     

去皮方式对黄桃渗透脱水组合干燥特性及理化品质的影响

为探究去皮方式对黄桃渗透脱水组合干燥特性及理化品质的影响,以金童8号黄桃为原料,分别采用手工去皮、碱液去皮、超声-碱液去皮和过热蒸汽去皮处理样品,测定其果肉得率。系统分析渗透脱水过程中黄桃果肉水分损失量(WL)、固形物增加量(SG)以及热泵干燥过程中水分和干燥速率变化情况,测定黄桃果干的类胡萝卜素含量、色泽、质构、微观结构和果胶溶出率。结果表明:渗透脱水组合干燥过程中,WL和SG随时间呈非线性增加的趋势,水分比和干燥速率随时间的延长均降低,Peleg模型可较好地(R20.95)模拟渗透脱水过程中的WL。经超声-碱液去皮处理的黄桃果肉得率(0.96 g/g)最高,果干的类胡萝卜素含量(71.14μg/g)和果胶溶出率(0.23 g/g)均高于其它组,色泽保持最好,即ΔE值(2.42)最小,b*最高(42.82),且硬度(2 019.54 g)和咀嚼性(1 087.72)适中。研究表明超声-碱液是一种有效的桃去皮技术。     

新疆薄皮核桃果仁去皮技术的研究

因为核桃仁外有一层种皮,它含有色素和苦涩味等成分,会严重影响产品的质量,所以必须将它去除.在给核桃仁去皮时可分为两种方法:一、加热煮沸法,可直接放入蒸馏水中加热至沸腾,闷制一定时问后取出,手工进行去皮.实验结果表明焖制46min时较容易完全去皮,质地较脆,时间延长,去皮更容易,但质地变差.二、碱液浸泡去皮法,选用NaOH溶液和Na2CO3溶液,在常温和热烫条件下对溶液浓度、浸泡时间进行考察,以去皮效果为考察指标并设计等级量化,结果表明:用NaOH溶液去皮,常温或热烫条件下欲达到完全去皮会使核仁的颜色有所变化,核仁品质降低,而用Na2CO3溶液可选用1.5%的Na2CO3溶液,温度75℃,加热15min这一方案,去皮后仁的色泽质地都较好.通过比较,加热煮沸法效果较好,可较好地的保障了核仁的品质.     

干灰枣去皮工艺优化及其活性成分变化

本研究以新疆干灰枣为试材,优化碱液去皮工艺,采用ABTS⁺自由基的清除能力与铁还原力评价抗氧化活性,采用液相色谱-质谱(LC-MS/MS)分析其代谢物的变化;以色泽、风味、质地、去皮率等为考察因素,结合去皮前后干灰枣的抗氧化活性和其功效成分变化,采用单因素和响应面试验优化最佳去皮工艺。结果表明,最佳工艺组合为碱液浓度3%、去皮时间3 min、去皮温度79℃。在此工艺条件下,干灰枣去皮率达到99.99%,感官评分最高为80.50±0.50分;与去皮前相比,去皮后枣肉的总酚含量、可溶性固形物含量和ABTS⁺自由基的清除能力与铁还原能力均呈下降趋势(P<0.05);通过LC-MS/MS对干灰枣去皮前后的功效成分进行分析,共鉴定出968种代谢物,通过KEGG富集分析发现,黄酮类化合物和核苷酸类化合物是干灰枣去皮处理过程中损失的主要功能成分。本研究采用多种手段综合评价了红枣碱液去皮工艺,为新疆灰枣进一步精细加工生产提供了理论依据。     

基于品质模型的黄桃去皮工艺优化及应用

黄桃加工中常用碱液去皮方法进行前处理,然而该工艺环节对产品品质定量影响的研究手段和工具较缺乏。本文采用"未反应核模型"建立了黄桃碱液去皮的定量化品质模型。通过96种处理【4个浓度(0.2,0.4,0.6,0.8 mol/L)、4个温度(70,80,90,95℃)和6个去皮时间(1,2,3,4,5,6 min)】,建立质量损失模型,以预测质量损失;建立了黄桃碱液去皮时间与温度、浓度和去皮厚度的函数,以预测去皮时间并优化去皮工艺;建立了去皮过程中质地随热效应改变的模型,以评估黄桃质地;同时建立了适用于实际应用的去皮时间随温度、浓度和去皮厚度变化的模型,为指导黄桃碱液去皮提供理论依据。     

新型番茄真空去皮生产线

番茄制品是果蔬制品的重要组成部分,全世界目前年产番茄约6千万吨,1988年除中国以外的28个主要生产国产量达63316000吨,其中半数以上用于加工,其制品有番茄酱和调味制品及整番茄。在整番茄罐头中则以去皮整番茄为优。但番茄去皮则由于其果实软烂而较困难,一般有碱液去皮和真空去皮两种,其中真空去皮由于其无环境污染、对产品无化学物质接触而深受欢迎。但研制一个适用的     

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.     

Understanding Tomato Peelability

Approximately 75% of all tomatoes in the United States are consumed as processed and 25% as fresh. One of the first steps during processing involves removal of the peel and, unfortunately, more than 25% of the fruits (as measured by total weight) can be lost due to overpeeling. Additionally, conventional peeling applications have a negative environmental impact. Given the great potential economic benefits, many scientists have conducted research to attempt optimizing or predicting peeling performance when processing tomatoes. The literature regarding tomato peelability is contradictory in many cases; and several topics have been subject to ample debate over the years. Divergent conclusions are probably not due to faulty investigations, but rather to the extreme variability found among tomato cultivars, the effect of growing seasons, and maybe even the effect of climatic conditions on the day of harvest or during transportation to the processing plants. This review provides an in‐depth background needed for a better understanding of tomato physiology, maturation, and composition, as these could possibly influence the ease of peeling or “peelability.” The research studies directly involved with peeling tomatoes and predicting peelability are discussed in this paper as well. Different peeling methods, peeling grading scales, and fruit tagging procedures are presented, as well as experiments evaluating the effect that fruit defects, maturity, growing conditions, and other factors can have on the ease of peeling. Novel approaches for peelability prediction by means of spectroscopic and magnetic resonance technology are also discussed in this review.     

红外表面加热结合冷冻处理对葡萄自动脱皮效果的影响

为了实现对冷冻葡萄的快速、高效脱皮,采用冻前红外表面加热处理和冻后红外表面加热处理2种方式,探索不同时间红外表面加热预处理结合冷冻手段对葡萄自动脱皮效果的影响。结果表明,冻前红外表面加热处理5 min以上能够使葡萄果皮出现明显的开裂现象,自动脱皮效果明显,然而过长时间的红外处理也会导致葡萄硬度、颜色等指标的下降。冻后短时红外处理能够更好保持葡萄的品质,1 min的红外表面加热能够保证葡萄在未解冻的前提下出现裂口,从而使得后续可以采用各种手段使葡萄实现自动脱皮。     

超声协同钙浸渍对樱桃番茄贮藏过程中 番茄红素和品质特性的影响

通过研究超声协同钙浸渍处理对樱桃番茄贮藏过程中理化品质和番茄红素的影响,阐明了超声协同钙浸渍提高樱桃番茄品质特性的原因.采用质构仪、色差计和高效液相色谱仪研究了樱桃番茄贮藏过程中硬度、色泽和番茄红素含量的变化,同时利用核磁共振技术分析了樱桃番茄贮藏过程中番茄红素结构特性的变化.研究结果表明:超声协同钙浸渍处理可促进钙离...     

Preparative separation and purification of lycopene from tomato skins extracts by macroporous adsorption resins

In order to separate and purify lycopene from tomato skins extracts (lycopene oleoresin) with macroporous adsorption resins (MARs), the adsorption properties of twenty-four kinds of MARs were evaluated. The results showed that LX-68 had higher separation efficiency than other resins. Based on the static experiments with LX-68, it was found that the experimental data fitted best to the pseudo-second-order kinetics model and Langmuir isotherm model. The separation parameters of lycopene from tomato skins extracts were optimised through dynamic adsorption/desorption experiments with the column packed by LX-68. Through only one cycle treatment, the lycopene content in lycopene oleoresin increased 30.4-fold from 0.21% to 6.38%, with a recovery yield of 66.9%, which were determined by HPLC method. The results showed that MARs would provide useful help for the development of large-scale manufacture in the separation of lycopene from tomato skins extracts.     

Optimizing Processing Conditions for Chemical Peeling of Potatoes using Response Surface Methodology

Using Response Surface Methodology the effects of NaOH concentration (4–20%), process temperature (55–95°C) and time (1–7 min) was determined on the yield, peeling quality, unpeeled skin and total usage of NaOH. Also evaluated were titratable NaOH in the potato tissue, NaOH penetration and “heat ring” depths during one stage chemical peeling of potatoes (Huincul variety). The best peeling quality, maximum yield and minimum total usage of NaOH was obtained for the following ranges: concentration, 11–13%, time 5–5.70 min and temperature, 90–95°C. The maximum temperature for which the “heat ring” and NaOH penetration depths were equal was 72°C where, at 20% NaOH and 7 min, peeling quality was very good and “heat ring” was absent.     

Tomato peeling by ohmic heating: Effects of lye-salt combinations and post-treatments on weight loss,peeling quality and firmness

Ohmic heating without lye has shown promise in tomato peeling; however the use of lye is known to yield high peeled-product quality. This investigation was aimed at determining whether a combination of ohmic heating and low lye concentrations could be synergistic. The results indicated that 0.01/0.5% NaCl/KOH at 2020 V/m was the best condition for tomato peeling in terms of quality, weight loss, and peel cracking time. Further, the treatment showed weight loss that was not significantly different from conventional lye peeling at 7% NaOH and 7% KOH (p < 0.05). NaCl/NaOH mixtures also showed good results, but the quality of products was lower than that using the same concentration, but a higher field strength with NaCl/KOH mixtures. However, no improvement was found using NaCl/CaCl₂ and NaCl/NaOH/CaCl₂ mixtures which were also found difficult to use due to turbidity and cleaning difficulties. A post-peeling treatment by ohmic heating was investigated to improve firmness of ohmically peeled tomatoes. It was found that the best conditions were 2% CaCl₂ solution at a field strength of 403 V/m for 1 and 5 min, and 484 V/m for 5 min.Industrial RelevanceOur earlier work had shown that ohmic heating resulted in peeling of tomatoes that were immersed in salt solutions. The current work details the impact of using small concentrations of lye (either sodium or potassium hydroxide) on peeling loss and quality. Also, we investigate the potential use of calcium chloride, both as peeling solution or as a post-peeling infusion as it impacts firmness of tomatoes. We show that there are ranges of operating conditions which provide yield and quality comparable to conventional lye peeling at far lower lye concentrations, resulting in potentially significant environmental benefit to companies currently using lye peeling.     

Dry-peeling of Tomato by Infrared Radiative Heating: Part I. Model Development

Infrared (IR) dry-peeling of tomatoes has emerged as a nonchemical alternative to conventional peeling methods using hot lye or steam. Successful peel separation induced by IR radiation requires the delivery of a sufficient amount of thermal energy onto the tomato surface in a very short duration. The objective of this study was to understand the transient heat transfer phenomena during IR dry-peeling by developing a computer simulation model. Modeled tomatoes with realistic shapes and different sizes were employed to predict the temperature distributions on their surface and interior during a typical 60 s IR heating. IR radiation was postulated as a mathematically gray-diffuse radiation problem based on the enclosure theory. Radiation heat transfer model combining heat conduction and convection was solved numerically in COMSOL by using a finite element scheme. Changes of tomato thermal properties and phase change of water inside tomato tissues due to temperature increase were considered in the model to improve the prediction accuracy. The developed model can further be used to study the effects of various engineering parameters on IR heating performance relevant to tomato peeling quality and efficiency. Numerical modeling of the heat transfer mechanism provides in-depth understanding of the rapid surface heating characteristics of IR in the tomato dry-peeling process.     

CAN WE PREDICT PEELING PERFORMANCE OF PROCESSING TOMATOES?

Tomato processors are increasingly interested in being able to predict whether tomatoes will peel well, and therefore, yield high‐value processed tomatoes. We describe two statistical models for peeling applied to multiple years of data. One model is appropriate for perfect or defect‐free tomatoes, and the second model is valid for the normal population of tomatoes obtained following mechanical harvesting. The ability to peel perfect tomatoes was significantly affected by exposure of tomatoes to temperatures greater than 100F, by fruit weight and by pericarp wall thickness. The peelability of a normal population of tomatoes was influenced by tomato weight and width as well as degree‐days and exposure to temperatures greater than 90F. Thickness of the pericarp walls and red layer positively affected the peelability of normal tomatoes. The ability to predict tomato peelability using statistical models may improve the quality of processed tomatoes and may result in more efficient commercial peeling operations.     

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.