漂烫对速冻薯条品质及淀粉糊化度的影响研究

研究以夏波蒂为原料,利用两种漂烫工艺制备速冻薯条,采用感官评价评定薯条品质。为获得高品质的薯条,首先测定鲜薯的理化成分(水分、淀粉、还原糖);其次探究预热、漂烫工艺对薯条淀粉糊化度的影响;最后测定不同漂烫工艺下漂烫水的糖度。以薯条品质、淀粉糊化度及漂烫水糖度为评价指标,对漂烫工艺进行参数优化,得到最佳的漂烫工艺参数:85℃漂烫6 min而后75℃漂烫20 min。在此条件下薯条淀粉完全糊化,薯条炸后的感官评分高达95。研究结果表明:漂烫工艺对薯条品质有影响;随着漂烫时间和温度的增加,薯条的糊化度增大,漂烫水的糖度升高;高温短时与低温长时相结合的两步漂烫工艺更合理,该研究结果为薯条漂烫工艺的研究提供理论依据和技术支持。     

漂烫对真空油炸银杏果品质的影响

以大佛指银杏果为原料,研究漂烫温度和时间对银杏果POD酶失活时间、水分含量、淀粉糊化度,以及对真空油炸银杏果微观结构、质构、脂肪含量、色泽和感官品质的影响。结果表明:随着漂烫温度和时间的增大,POD酶失活时间逐渐缩短,而银杏果中淀粉糊化度和水分含量逐渐升高;漂烫时间越长真空油炸银杏果的脆性和色泽越好,但真空油炸银杏果的脂肪含量越高;100℃漂烫5min时银杏果真空油炸后能形成多孔状,且感官评分最高。综合考虑,采用100℃条件下对银杏果进行漂烫5min处理。     

真空油炸果蔬脆片预处理技术研究进展

真空油炸果蔬脆片品质优于常压油炸产品,近年来发展迅速。预处理技术可降低真空油炸果蔬脆片含油率,提高果蔬脆片品质。该文对漂烫、渗透、涂膜、冷冻、预干燥、超声波6种预处理方法的原理、特点进行综述,分析不同预处理方法对产品品质的影响,以期为高品质的真空油炸果蔬脆片的研究与开发提供参考。     

不同烫漂时间对真空油炸毛豆仁品质的影响

对生产中不同烫漂时间对真空油炸毛豆仁品质的影响进行了研究。实验结果表明,烫漂时间的长短(在0-10min内)对真空油炸毛豆仁的脆度、瓣的完整性以及色泽有明显影响,综合比较2-10min处理后产品的Vc含量和蛋白质含量,烫漂时间的长短对产品的营养物质损耗不是很大,烫漂时间对含油率影响较大,超过6min后,含油率下降不是很明显。综合比较表明,烫漂时间6min为最佳。     

油炸方式对高白鲑肌肉食用品质的影响

探究采用空气油炸锅获得传统油炸效果的途径,并比较2 种油炸方式下获得高白鲑肌肉食用品质的差异。通过对熟化后的鱼块进行肌肉损失率、质构、色泽测定,筛选出传统油炸工艺参数为170 ℃-100 s和180 ℃-80 s,空气油炸工艺参数为170 ℃-12 min和180 ℃-10 min。比较2 种油炸方式下高白鲑鱼块的肌肉基本营养成分差异,在获得相似感官品质条件下,空气油炸鱼块脂肪质量分数为16.21%～17.54%,低于传统油炸鱼块脂肪质量分数18.68%～20.33%。对加工后鱼块取肉进行风味物质检测和感官评定发现2 种油炸方式处理的鱼肉挥发性风味物质、游离氨基酸、呈味核苷酸和感官评分具有相似性。综上可知,空气油炸的高白鲑鱼块在外观、质构、营养成分、呈味物质及感官方面能与传统油炸达到类似效果并减少油脂的使用。     

预熟制对油炸猪肉丸品质的影响

探讨煮制、蒸制和微波3 种预熟制处理的加入对油炸猪肉丸品质的影响。以直接160 ℃油炸6 min的猪肉丸为对照,测定经过煮制、蒸制和微波预熟制加热处理10 min后160 ℃油炸2 min的猪肉丸的品质指标。结果表明：与对照组相比,煮制和微波预熟制显著影响油炸猪肉丸的色泽（P＜0.05）,蒸制处理对肉丸色泽影响不显著（P＞0.05）;不同预熟制处理对油炸猪肉丸的弹性和内聚性没有显著影响（P＞0.05）;微波预熟制后油炸猪肉丸的含水率和脂肪含量均显著下降（P＜0.05）,而煮制后油炸的猪肉丸含水率和脂肪含量均显著上升 （P＜0.05）,蒸制后油炸的猪肉丸含水率和脂肪含量变化不显著（P＞0.05）;经感官评定,煮制后油炸猪肉丸感官评分显著降低（P＜0.05）,蒸制和微波预熟制对油炸肉丸感官评分无显著影响（P＞0.05）。微波预熟制可用于生产低脂肪含量油炸制品。     

低温真空油炸小黄鱼加工工艺优化及包装方式对其贮藏品质的影响

以小黄鱼为研究对象,采用低温真空油炸技术研制休闲调理产品,优化了低温真空油炸加工工艺(预烘干温度和时间、真空油炸温度和时间等),比较了低温真空油炸和常压油炸产品的品质差异,并研究了包装方式对低温真空油炸小黄鱼贮藏品质的影响,以期为小黄鱼调理食品的开发提供理论依据和技术支撑。结果显示:小黄鱼低温真空油炸的最优工艺为预烘干温度50℃、烘干时间2 h、油炸温度95℃、油炸时间3500 s,油炸后离心脱油时间300 s。与常压油炸相比,低温真空油炸小黄鱼水分含量降低了12.48%,含油量降低了11.6%,L值提高了9.59%,综合感官评分更高。两种油炸方式小黄鱼产品的风味差异显著,真空油炸和常压油炸小黄鱼分别检测出21种和14种挥发性物质,其中真空油炸更利于醛类和醇类化合物的产生,风味更佳。通过比较不同包装方式真空油炸小黄鱼贮藏期间品质的变化,发现真空油炸小黄鱼气调包装效果优于常规包装,且70% N₂+30% CO₂包装效果优于100% N₂包装,最短货架期超过60 d。     

低温真空油炸粉葛片工艺优化及其品质分析

为实现粉葛的全质化利用,本文采用低温真空油炸工艺制备粉葛片。在单因素实验基础上通过正交试验优化了低温真空油炸粉葛片的制备工艺。结果表明,最优工艺为粉葛片厚度2 mm,油炸温度105℃,油炸时间35 min,漂烫时间3 min。在最优条件下粉葛片脆性值为989.35 g,脂肪含量为22.95%。此外,还比较了不同工艺制备的粉葛片品质。漂烫、冷冻处理后低温真空油炸粉葛片的脂肪含量较低,脆性值较高,而通过漂烫冷冻常规油炸所得粉葛片含水量（1.71%）和脆性值（597.54 g）最低,脂肪含量达62.24%。未漂烫粉葛片常规油炸后脂肪含量显著高于低温真空油炸所得粉葛片（P<0.05）,而脆性值无显著性差异（P>0.05）。油炸粉葛片香气物质以氮氧化合物、硫化物和有机硫化物为主,但是不同油炸所得粉葛片香味有明显差异。经油炸后粉葛片表面蜂窝状结构消失,通过漂烫冷冻低温真空油炸的粉葛片表面有少许孔洞,而在未冷冻的葛根片表面形成一层凝胶层。     

漂烫时间及贮藏温度对香椿嫩芽品质的影响研究

以香椿嫩芽为研究对象,研究不同漂烫时间及贮藏温度对香椿嫩芽品质的影响,以期为香椿嫩芽的加工提供理论指导。以烫漂后香椿嫩芽感官及品质指标VC、多酚、黄酮、可溶性蛋白、亚硝酸盐及多酚氧化酶(PPO)各项变化对香椿嫩芽品质进行综合评价。结果表明:较短的漂烫时间可以保持香椿嫩芽外观及口感;对香椿嫩芽营养成分影响较小,烫漂可显著降低香椿嫩芽中的亚硝酸盐含量且可显著降低多酚氧化酶酶活性;在-2℃贮藏180 d,香椿嫩芽仍保持较好的品质。因此0.5 min为香椿嫩芽最佳烫漂时间,-2℃贮藏可以较好保持烫漂香椿嫩芽的品质。     

香菇脆片真空油炸过程中传热规律研究

真空油炸过程中同时发生热量和质量传递现象,这些现象对产品的品质和安全控制极为重要。该文研究真空度、油炸温度、预处理(漂烫、漂烫+浸渍+涂膜)对香菇脆片真空油炸过程中对流传热系数(h)的影响,结果表明:h值的变化趋势是先增大后减小;达到峰值的时间都在300 s～600 s;油炸温度越高,峰值越高;真空度越高,峰值越高;在真空油炸后期,油炸温度和真空度低的香菇脆片对流传热系数值高;油炸条件相同,漂烫处理香菇脆片的最大对流传热系数值高于漂烫+浸渍+涂膜处理香菇脆片。     

土豆加工工艺的探讨

<正> 土豆片和土豆条等土豆加工产品,是深受消费者欢迎的休闲食品,在市场上占有一定的位置。对于这个具有潜力的市场,从事土豆片生产的加工商不断寻求开发具经济效益的生产技术与设备。事实上,土豆片的加工技术包括多个步骤,如去皮、蒸煮、干燥、油炸和冷冻等。本文集中介绍新式的土豆片蒸汽去皮和干燥技术。     

Changes in glycoalkaloid and nitrate contents in potatoes during French fries processing

The purpose of this investigation was to determine the influence of various stages of French fries processing on the contents of glycoalkaloids and nitrates in potatoes. The material for the study comprised samples of two potato varieties, Santana and Innowator, collected from nine stages of a French fries production line. Based on the results of the research carried out, it was found that the processes applied during French fries production had a significant influence on the decrease in glycoalkaloid (chaconine and solanine) and nitrate contents in both intermediate products and the final product in comparison with the raw material. The highest amounts of glycoalkaloids and nitrates were removed during peeling, blanching and frying. In the processed potatoes the ratio of chaconine to solanine decreased. French fries ready for consumption contained only 3–8% of the glycoalkaloids and 5–6% of the nitrates found in the raw material. Copyright © 2004 Society of Chemical Industry     

Characterization of crispness of French fries by fracture and acoustic measurements,effect of pre-frying and final frying times

The influence of pre-frying and final frying time on the crispness of French fries was evaluated by simultaneous analysis of the fracture and acoustic properties during instrumental simulation of human chewing. The analysis of the frequency distribution of the force and sound events corresponding to the crust of the French fry reflected an effect of both pre-frying and final frying time on instrumental crispness. Up to 60 s pre-frying, an increase in the number and magnitude of force and sound events was found, which reflect an increase in crispness. The increase in final frying time increased crispness, but it cannot counterbalance a lack of pre-frying. The moisture content of the whole French fries cannot explained the effect of pre-frying on crispness. Conversely, the effect of pre-frying can be explained when considering only the moisture content of the crust. Pre-frying may allow an easier loss of water from the crust during final frying, which will enhance its crispness.     

Microwave heating instead of blanching to produce low-fat French fries

Blanching pretreatment is necessary for preparing French fries, but it causes water consumption and nutrient outflow. This work was aimed to investigate the effects of microwave (MW) pretreatment instead of blanching on the quality of fries, evaluated via changes to microstructure and crust characteristics. First, MW pretreatment could inactivate polyphenol oxidase in fresh-cut potato strips to inhibit enzymatic browning. Subsequently, the fries after proper MW pretreatment (60 s) had a golden appearance and better texture. As compared with the blanching process, the oil content of the fries obtained by MW pretreatment was decreased sharply from 41.3% to 18.1%. The results of scanning electron microscopy showed that MW pretreatment significantly altered the crust and internal microstructure of fries. Specially, it was found that the MW pretreatment made the fries form a thicker “protective crust” (1.81 μm), which was crucial to prevent oil adsorption during the frying and improve texture.Industrial relevanceBlanching is a traditional thermal processing technique that was once widely used in French fries around the world. However, blanching has some drawbacks, such as slow heat conduction, long processing time, substantial loss of soluble nutrients, massive water wastage, and even increased oil content of the fries. Meanwhile, MW heating is known for its high efficiency. The fries obtained with proper MW pretreatment are of good quality, but the oil content is drastically reduced compared to conventional blanching pretreatment. So, the above findings may provide helpful information to guide effective strategies for applying MW heating instead of blanching in the preparation of fried potato foods.     

Modeling texture kinetics during thermal processing of potato products

ABSTRACT:  A kinetic model based on 2 irreversible serial chemical reactions has been proposed to fit experimental data of texture changes during thermal processing of potato products. The model links dimensionless maximum force F*_MAX with processing time. Experimental texture changes were obtained during frying of French fries and potato chips at different temperatures, while literature data for blanching/cooking of potato cubes have been considered. A satisfactory agreement between experimental and predicted values was observed, with root mean square values (RMSs) in the range of 4.7% to 16.4% for French fries and 16.7% to 29.3% for potato chips. In the case of blanching/cooking, the proposed model gave RMSs in the range of 1.2% to 17.6%, much better than the 6.2% to 44.0% obtained with the traditional 1st-order kinetics. The model is able to predict likewise the transition from softening to hardening of the tissue during frying.     

The influence of French fries processing on the glycoalkaloid content in coloured-fleshed potatoes

French fries made from coloured-fleshed potatoes may be interesting alternative to the traditional snacks for consumers. However, potatoes contain glycoalkaloids (TGA), so potato tubers and obtained fried snacks should be subjected to comprehensive examination. The aim of this study was to determine the effect of different stages of French fries processing on the content of TGA (α-solanine and α-chaconine) in the red- and blue-fleshed potatoes, in semi-products and ready-to-eat products. It was stated that during the processing of French fries prepared from coloured-flesh potato varieties significantly decreased the content of TGA (α-solanine and α-chaconine) in the samples obtained at different stages of the process compared to the raw material. Potatoes with blue-fleshed of Vitelotte variety and red-fleshed of Highland Burgundy Red variety can be used to French fries processing due to their low content of TGA (in unpeeled and peeled potatoes). However, Blue Congo variety with blue-fleshed should not be applied to French fries processing, because of high TGA content in raw material and first of all in peeled potatoes flesh. The peeling process of coloured-fleshed potatoes decreased in TGA content on average by about 50 %, cutting process on average by about 53 %, whereas blanching on average by about 58 % compared with the raw material. The highest decrease in TGA content was caused by frying process. The mean values were about 97.5 % in ready-to-eat French fries. In French fries after I and II steps of frying, the ratio α-solanine to α-chaconine was lower (1.0:2.0) than in unpeeled potatoes (1.0:2.3).     

Changes of polysaccharide content and texture of potato during French fries production

The purpose of the present study was to determine the changes in non-starch polysaccharide and lignin contents of potato during French fries production and also the relationship between the texture of the finished product and half-products, as a result of processing at each stage under investigation. The samples for laboratory studies were taken from potato tubers, strips and French fries collected from nine locations of a technological line. The greatest changes in non-starch polysaccharide content and texture of potatoes resulted from blanching and frying. The texture of French fries was mainly affected by pectin and cellulose. The texture of French fries can be predicted from the measurements of the texture of potato strips after blanching.     

Effects of potato strip size and pre-drying method on french fries quality

Potato strips of 8 mm × 8 mm and 10 mm × 10 mm after blanching were pre-dried using two methods: convective and vacuum-microwave (VM). A two-stage frying in rapeseed oil was applied to prepare French fries from pre-dried potato strips. The quality of French fries in terms of texture, oil content and color was analyzed based on the results from instrumental tests and sensory evaluation. Using vacuum-microwave instead of hot air resulted in substantial shortening of the potato strips’ pre-drying time and decreasing the fat content in French fries. Pre-drying of potato strips, particularly by VM method, improved color and increased maximum cutting force as well as maximum cutting work estimated for French fries. French fries prepared from potato strips of 10 mm × 10 mm exhibited lower lightness, higher fat content and higher cutting strength compared with those made from potato strips of 8 mm × 8 mm. Based on the sensory results, it was found that the best French fries were those from pre-dried potato strips of 8 mm × 8 mm, independently of the pre-drying method used, and the worse were those from potato strips of 10 mm × 10 mm pre-dried with the convective method. SEM images confirmed structural changes occurred in potato tissue during pre-drying and frying.     

Effect of processing and packaging conditions on quality of refrigerated potato strips

Abstract: Although sulfiting agents are commonly used in the fresh‐cut potato industry, concerns about further regulatory restrictions on sulfite use and consumer fear of sulfite‐treated foods have lead to increased research in alternative processing methods. The objective of this study was to determine processing and packaging techniques to achieve a safe and high‐quality potato strips with a 4 wk minimum refrigerated shelf life. Potato strips were 1st blanched at low temperature (60 °C) in 0.5% CaCl₂ solution for 20 min and then 2nd blanched at high temperature (approximately 98 °C) in water for 5 min. Blanched strips were packaged in a near‐aseptic environment or treated in‐package with gaseous ozone, sodium metabisulfite (SM) solution, or FIT Fruit and Vegetable Wash? (Procter and Gamble Co., Cincinnati, Ohio, U.S.A.) and then stored at 7 ± 1 °C for 28 d. No significant difference was observed in lightness of near‐aseptically packaged fries, FIT‐treated fries, and frozen fries; however, less color difference was determined in near‐aseptically packaged fries and FIT‐treated fries compared to frozen fries. Gaseous ozone treatment decreased color quality of potato strips, significantly. The highest after‐frying peak force was observed in FIT‐treated strips. There was no significant difference in oil absorption of refrigerated and unprocessed strips. These results indicate that either near‐aseptic packaging or in‐package FIT treatment are the better alternatives for blanched potato strips to extend shelf life and maintain quality. Practical Application: In this study, several processing conditions and packaging methods were evaluated to improve quality and extend shelf life of refrigerated potato strips. Results indicate that the combination of 2‐step blanching and near‐aseptic packaging was an effective nonchemical processing method, giving 28 d refrigerated shelf life. Similarly, FIT Fruit and Vegetable Wash? proved to be an effective chemical alternative to sulfites and avoids the allergen concern.     

Fat Uptake in French Fries as Affected by Different Potato Varieties and Processing

ABSTRACT: The uptake of lipid into French fries was investigated using two varieties of potato ('Russet Burbank' and 'Agria') and the New Zealand sweet potato, Ipomoea batatas , (kumara). The variety of potato used had a significant effect on lipid uptake, with 'Agria' having the lowest lipid content. The different cellular structures may have affected the fat uptake in the French fries by influencing either the loss of moisture during finish-frying or the damage done to the original anatomy during processing before pre-frying. The French fries that had undergone frozen storage had a higher amount of lipid contained in their inner core than did those that had been either chilled or prepared freshly for frying.