Effects of ultrasound-assisted frying on the physiochemical properties and microstructure of fried meatballs

The aim of this study was to investigate the effects of power ultrasound (0, 200, 400, 600 and 800 W, 20 kHz) on the quality of fried meatballs. The frying time and frying temperature were also considered as fixed factors. The meatballs were fried for 8, 12 and 16 min at 120, 140 and 160 °C. Results showed that the ultrasonic groups saved about 1 to 3 min than the control group to 80 °C. Hardness, springiness, cohesiveness and chewiness of fried meatballs were significantly different among different ultrasonic treatments (P < 0.05). As for colour, the ultrasonic treatments could significantly increase the L*values. Cooking yield was from 82.58% to 85.50% in ultrasonic treatments at 120 °C for 8 min. High moisture retention and cooking yield were shown in fried-assisted ultrasound treatments and were consistent with the microstructure of scanning electron microscopy (SEM). Our data show that ultrasound-assisted frying could improve the quality of meatballs.     

油炸工艺对油炸鸡腿品质和安全性的影响

研究油炸温度-油炸时间-新旧油比例对油炸鸡腿丙烯酰胺含量和品质特性的影响,优化油炸工艺,控制丙烯酰胺生成量,改善产品质量。分别测定了在150、160、170℃油炸11、12、13min过程中鸡腿丙烯酰胺生成量和品质的变化。结果显示:使用新油油炸温度为150℃油炸11min时水分含量最高,脂肪含量最低;油炸用油为新旧油比例1:1;油炸温度为150℃,油炸12min时油炸鸡腿的外观金黄;使用新油在150℃下油炸11min时油炸鸡腿鸡皮中丙烯酰胺含量最低;使用新旧混合油油炸温度为150℃油炸12min时油炸鸡腿鸡肉中丙烯酰胺含量最低。结合油炸鸡腿的品质和安全指标综合考虑后确定油炸鸡腿的最佳油炸工艺参数为:新旧油比例为1:0,油炸温度为150℃,油炸时间为11min。      

Reduction in hydroxymethylfurfural content in ‘churros’, a Spanish fried dough,by vacuum frying

This work explores the advantages of vacuum frying of ‘churros’, a Spanish dough pastry, compared to standard deep‐fat frying. Oil uptake, texture change, colour development, nonenzymatic browning and hydroxymethylfurfural (HMF) concentration were analysed at different frying conditions. The results obtained during vacuum frying at 100, 120 and 140 °C and 21 kPa were compared with those obtained at atmospheric pressure at 140 and 180 °C. For the same final water content, the vacuum fried ‘churros’ showed no significant differences in the fat uptake compared to those fried at atmospheric pressure (P > 0.05). However, the vacuum fried dough had a much crunchier texture. The evolution of the CIELab a* coordinate and the browning measurement at 280 nm show that vacuum frying is able to slow down the development of browning tones. Furthermore, products can be obtained with an HMF content <1 mg kg^?1 of dry dough.     

煎炸油净化助滤剂在油炸鸡块生产中的应用

综述了煎炸油净化助滤剂脱除煎炸油中的游离脂肪酸、色素、极性化合物等杂质的吸附处理性能,以及其在油炸鸡块生产中的应用。经过滤处理后的煎炸油色泽浅黄,酸价由1．12mgKOH／g降低到0．12mgKOH/g,同时除掉70％以上的色素和大部分极性物,无异味,不再起泡冒烟,过滤净化效果显著。     

真空油炸胡萝卜片工艺研究与经济效益分析

胡萝卜营养丰富,但胡萝卜所固有的气味为很多人不习惯,为了除去胡萝卜特有的滋味和气味,加工成高品质、色、香、味、俱佳的松脆可口的胡萝卜片,对其影响胡萝卜的质量的因素进行了研究,确定其最佳工艺条件,并对其工业化生产进行了经济效益分析。     

Standardization of domestic frying processes by an engineering approach

An approach was developed to enable a better standardization of domestic frying of potato products. For this purpose, 5 domestic fryers differing in heating power and oil capacity were used. A very defined frying process using a highly standardized model product and a broad range of frying conditions was carried out in these fryers and the development of browning representing an important quality parameter was measured. Product-to-oil ratio, oil temperature, and frying time were varied. Quite different color changes were measured in the different fryers although the same frying process parameters were applied. The specific energy consumption for water evaporation (spECWE) during frying related to product amount was determined for all frying processes to define an engineering parameter for characterizing the frying process. A quasi-linear regression approach was applied to calculate this parameter from frying process settings and fryer properties. The high significance of the regression coefficients and a coefficient of determination close to unity confirmed the suitability of this approach. Based on this regression equation, curves for standard frying conditions (SFC curves) were calculated which describe the frying conditions required to obtain the same level of spECWE in the different domestic fryers. Comparison of browning results from the different fryers operated at conditions near the SFC curves confirmed the applicability of the approach.     

真空低温煎炸对油稳定性影响的研究

主要探讨了真空低温煎炸胡萝卜片后3种煎炸油的稳定性,研究了3种煎炸油的酸值、过氧化值、羰基值随煎炸时间的变化规律,并分析了它们之间的相关性.结果显示,与大豆色拉油相比,棕榈油和猪油有更高的煎炸稳定性;3种油的酸值、过氧化值、羰基值与煎炸时间存在着显著的相关性.     

油炸食品中丙烯酰胺分析方法研究进展

对食品中丙烯酰胺分析方法的研究进展进行了综述。主要包括GC-MS、LC-MS和LC-MS-MS方法分析食品中的丙烯酰胺以及一些国家机构规定的官方分析方法。另外,对现有分析方法的优缺点进行了评述,对食品中丙烯酰胺的分析方法进行了展望。     

真空油炸过程中干燥特性和产品品质变化的研究

研究了胡萝卜脆片真空油炸过程中干燥特性和产品品质的变化,结果表明:真空油炸过程属于传统的降速干燥过程,其水分和脂肪的变化符合一级反应动力学规律,利用非线性回归法求解得到了胡萝卜脆片水分和脂肪含量、干燥速率随油炸时间变化的方程;随着油炸时间的延长,胡萝卜脆片直径不断减小,厚度不断增加,油炸20min后,其直径和厚度皱缩度分别达到6%和4.5%;真空油炸胡萝卜脆片气孔数量不断增加,细胞结构变形程度增强。真空油炸过程中胡萝卜脆片脂肪主要分布于脆片的表面,冷却过程中脂肪逐渐向中心渗透,中心脂肪含量可达到60%。     

深度油炸过程煎炸油的氧化及其对油炸外裹糊鱼块品质的影响

目的 探究深度油炸过程煎炸油的氧化,并进一步研究煎炸油氧化对油炸外裹糊鱼块品质的影响。方法 分别采用棕榈油、大豆油、葵花籽油、小麦胚油在150、160、170、180、190℃下油炸外裹糊鱼块,测定煎炸油的酸价、过氧化值、黏度、介电常数以及油炸外裹糊鱼块外壳的水分含量、油脂含量、表面色度。结果 随着油炸温度的升高,煎炸油的游离脂肪酸含量增加,导致煎炸油的酸价、黏度和介电常数升高,过氧化值呈现波动下降的趋势;油炸外裹糊鱼块的水分含量逐渐减少,油脂含量逐渐增加,L*和b*呈递减趋势、a*呈递增趋势,且使用4种煎炸油的各项指标存在明显差异。结论 煎炸油的油炸温度和不饱和脂肪酸含量显著影响了煎炸油的氧化,导致外裹糊鱼块深度油炸过程中水分蒸发和油脂吸收有明显差异,最终影响了油炸外裹糊鱼块的品质。     

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。     

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。     

Effects of contact‐dehydrating sheets on preference for fried food and deterioration of frying oil

The purpose of this study was to investigate the effects of contact‐dehydrating sheets on preferences for fried food and the deterioration of frying oil. Mackerel or chicken breast were dehydrated by wrapping with the contact‐dehydrating sheets at 4°C for 1.5 h and subsequently fried at 180°C for 3 min; those were referred to as the dehydrated samples. The same fried materials not wrapped with the contact‐dehydrating sheets were referred to as the control. The frying procedure was repeated 15 times under the above conditions and the amount of frying oil was adjusted to 1000 g by addition of new oil each time. Sensory analysis showed that the dehydrated samples were preferred to the control. Acidic values, anisidine values and ΔE values of the frying oil used for the dehydrated mackerel were significantly lower than for that used for preparing the control. These results indicate that the use of contact‐dehydrating sheets for the dehydration of the frying materials was effective in both significantly increased preference for the fried food and the retardation of the deterioration of the frying oil. Copyright © 2004 Society of Chemical Industry     

Effects of osmotic pretreatment and frying conditions on quality and storage stability of vacuum-fried pumpkin chips

The effects of osmotic (OP), ultrasound-assisted osmotic pretreatment (UAOP) and frying conditions on quality and storage stability of vacuum fried pumpkin chips were investigated. The pumpkin samples were pretreated in maltodextrin solution and subsequently fried at different temperatures (90–110 °C) and time periods (10–30 min). The results demonstrated that the moisture content, water activity, lightness, yellowness and carotenoid content of the fried chips decreased, while oil content, hardness and a* (dark brown colour) value increased with increasing frying temperature and time. UAOP reduced about 16.0% of oil absorption and enhanced approximately 70% of carotenoid retention in the fried chips. UAOP samples were also more stable during storage than the untreated ones, indicated by lower degradation kinetics constants of key quality parameters. The proposed pretreatment could be an effective method for food industries to develop vacuum fried pumpkin chips with improved quality and stability.     

Impact of the frying temperature on protein structures and physico-chemical characteristics of fried surimi

In this work, protein structures and properties and physico-chemical characteristics of surimi fried at different temperatures were studied. The effect of frying on surimi protein structure was characterised by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE), intrinsic fluorescence, surface hydrophobicity, intermolecular interaction and Fourier transform infrared spectroscopy (FT-IR). SDS-PAGE analysis observed the appearance of new peptide bands and the weakening of myosin heavy-chain and actin bands after frying. In addition, frying damaged the hydrogen bond and ionic bond but promoted formation of the disulphide bond. Moreover, β-sheet and random coil were increased after frying, while α-helix and β-turn were decreased. After frying, the surface hydrophobicity of fried surimi decreased and the fluorescence maximum emission wavelength showed a red shift. The above changes indicated occurrence of protein denaturation and degradation, which were dependent on the frying temperature. Moreover, the effect of the frying temperature on physicochemical properties of fried surimi was characterised by measuring the hardness, oil absorption, porosity and water absorption capacity of fried surimi. The moisture loss, oil uptake, porosity and water absorption capacity of the fried surimi increased gradually with the frying temperature. However, the hardness of fried surimi was not positively correlated with the frying temperature but strongly dependent on the porous structure. These results showed that the physico-chemical properties of the fried surimi were dependent on not only degree of protein denaturation but also the porous structure.     

真空油炸甘薯脆片的研究

以甘薯为原料,对真空油炸甘薯脆片加工工艺进行优化实验,为获得优质甘薯脆片产品的开发提供了参考依据。     

Overview on mitigation of acrylamide in starchy fried and baked foods

Acrylamide in fried and baked foods has the potential to cause toxic effects in animals and humans. A major challenge lies in developing an effective strategy for acrylamide mitigation in foods without altering its basic properties. Food scientists around the world have developed various methods to mitigate the presence of acrylamide in fried food products. Mitigation techniques using additives such as salts, amino acids, cations and organic acids along with blanching of foods have reduced the concentration of acrylamide. The use of secondary metabolites such as polyphenols also reduces acrylamide concentration in fried food products. Other mitigation techniques such as asparaginase pre‐treatment and low‐temperature air frying with chitosan have been effective in mitigating the concentration of acrylamide. The combined pre‐treatment process along with the use of additives is the latest trend in acrylamide mitigation. © 2018 Society of Chemical Industry     

Comparative study of physical and sensory properties of pre-treated potato slices during vacuum and atmospheric frying

The objective of this research was to study the effect of different processing conditions on physical and sensory properties of potato chips. Potato slices of Desirée and Panda varieties (diameter: 30 mm; thickness: 3 mm) were pre-treated in the following ways: (i) control or unblanched slices without pre-drying; (ii) blanched slices in hot water at 85 °C for 3.5 min and air-dried at 60 °C until a final moisture content of ∼0.6 kg water/kg dry solid; (iii) control slices soaked in a 3.5 kg/m³ sodium metabisulphite solution at 20 °C for 3 min and pH adjusted to 3. Pre-treated slices were fried at 120 and 140 °C under vacuum conditions (5.37 kPa, absolute pressure) and under atmospheric pressure until they reached a final moisture content of ∼1.8 kg water/100 kg (wet basis). An experimental design (3 × 2³) was used to analyze the effect of pre-treatment, potato variety, type of frying and frying temperature over the following responses: oil content, instrumental color and texture and sensory evaluation. Vacuum frying increased significantly (p < 0.05) oil content and decreased instrumental color and textural parameters. Sensory attributes, flavor quality and overall quality, were significantly improved using vacuum frying. The higher frying temperature (140 °C) increased ΔE, maximum breaking force, hardness and crispness and decreased L^* and b^* values. On the other hand, Panda potato variety improved the color of the product. A great improvement on color parameters was obtained using sulphited potato slices instead of the other pre-treatments. Although, the better flavor was obtained for control potato chips, no significant differences were found for overall quality between control and sulphited potato chips. Significant correlations (p < 0.01) between sensory and instrumental responses were found.     

煎炸食物吸油机理探讨

探讨了煎炸食物生产过程中的油脂吸收机理,包括毛细管吸油机理、冷凝机理、表面活性剂理论及粘附理论等,理解这些吸油机理,有助于人们更好地控制煎炸食物的油脂吸收过程。     

低温真空油炸薯片生产工艺及其贮藏条件的研究

对马铃薯片进行低温真空油炸生产工艺的基础性研究,分析薯片在贮藏过程中水分、脂肪和VC含量的变化,并探讨等温吸湿规律。通过单因素试验确定最优的油炸工艺参数为温度105℃,时间20min,真空度0.090MPa;离心脱油的最佳条件为脱油转速400～500r/min,时间5～7min,真空度0.090MPa。研究结果对低温真空油炸薯片技术具有很好的指导和促进作用,同时改善了现在油炸薯片的品质和提高了能源利用率。