Understanding and predicting sensory crispness of deep‐fried battered and breaded coatings

Crusted crispness refers to coatings with a dry and brittle surface contrasting a high‐moisture core; it is desirable for the enjoyment and quality of deep‐fried goods. This study aims to investigate instrumental measurements and sensory measurements of crispness. Deep‐fried breadcrumb coatings of eight sizes were investigated: 4.0 mm, 2.8 mm, 2.0 mm, 1.4 mm, 1.0 mm, 710 μm, 500 μm, and 355 μm. Sensory profiling was carried out to develop a tailored lexicon for deep‐fried battered and breaded shrimp. Principal component analysis highlights that large breadcrumb sizes correlate with crispness, hardness, particle size, surface color, color uniformity, surface irregularity, total porosity, maximum force, area, drop in force, number of sound peaks, and sound pressure level. Agglomerative hierarchical clustering was used to confirm clustering of samples according to breadcrumb size. Multiple factor analysis confirmed overall correlation between sensory measurements and instrumental measurements (RV = 0.810). Partial least squares regression was used to develop a predictive model for crispness from instrumental measurements (R² = .854). The use of texture analysis and Acoustics provide information of the structures strength and deformation behavior, while X‐ray microCT provides a high resolution and noninvasive method that acquires information on the internal morphology. These instrumental methods collectively demonstrate the relationship between microstructure to sensory. This study investigates how a change in the microstructure of deep‐fried battered and breaded coatings affect crispness perception. These changes were investigated analytically and by using a sensory panel, this is important from a manufacturing perspective in order to understand what the major contributors are to a crisp texture. The key highlights of this study include both instrumental measurements and sensory measurements can be used to measure crispness as both types of testing are correlated. Changes in the size of breadcrumbs affect both instrumental measurements and sensory measurements. A predictive model can be re‐simulated to allow prediction of crispness in deep‐fried battered and breaded coatings.     

Characteristics and oil absorption in deep‐fat fried batter prepared from ball‐milled wheat flour

BACKGROUND: The porous structure generated during frying influences oil absorption and textural qualities. The alteration in physical properties of wheat flour is suspected to affect the structure formation. The present study investigated the effect of physicochemical changes in wheat flour by the ball‐milling process on structure formation and consequently oil absorption of a fried wheat flour batter model. RESULTS: Batter models containing 600 g kg^?1 moisture were made of 0–10 h ball‐milled wheat flour and then fried in frying oil at 150 °C for 1–7 min. The samples made of milled flour possess larger pores and exhibit lower oil absorption than sample made of 0 h milled flour. The fracture force of a fried sample prepared from 5 and 10 h milled flour is lower than that of a sample prepared from 0 h milled flour. CONCLUSION: The decrease in glass transition temperature (T_g) and melting temperature (T_m) of milled flour affect the microstructure formation in the fried wheat flour batter. The microstructure is responsible for oil absorption and fracturability in fried food. The samples made of flour of longer ball‐milling time have lower oil absorption and higher crispness. Ball‐milling may be a tool to produce mechanically modified wheat flour which can reduce oil absorption for fried batter. Copyright © 2009 Society of Chemical Industry     

配方和预干燥时间对油炸裹层面糊含水量、含油量的影响

为了解裹层配方、油炸时间和预处理条件对油炸裹层吸油量的影响,研究了烘箱预干燥0、15和30min的四种(纯小麦粉,添加羟丙基甲基纤维素(HPMC),添加黄原胶和添加鱼鳞胶原蛋白)配方的面糊在180℃油炸条件下,水分含量和油含量随油炸时间的变化情况,及裹层在油炸过程中的传质动力学。结果表明:添加了HPMC和黄原胶的裹层在油炸过程中的含水量高,吸油量低。预干燥条件会影响裹层在油炸过程中的传质速率,预干燥时间越长,水分扩散率越低,油脂移动的速率也越低。菲克第二定律和一级动力学方程的预测结果与实验结果拟合度较高,可以很好的描述水分扩散和油脂移动过程。      

鱼鳞胶原蛋白对油炸壳层品质的影响

为了改善油炸食品的品质,研究了向裹层面糊中添加玉米淀粉、马铃薯淀粉、麦芽糊精、谷朊粉、大豆分离蛋白、羟丙基甲基纤维素、黄原胶、瓜尔胶和鱼鳞胶原蛋白对180℃条件下油炸2min壳层的含水量、吸油量、L*、a*、b*、色度、色彩角和脆度的影响,并考察了鱼鳞胶原蛋白对油炸壳层品质的影响。结果表明:添加鱼鳞胶原蛋白可改善油炸壳层的金黄色泽且效果优于实验中其他类添加物。玉米淀粉、马铃薯淀粉和黄原胶可降低壳层7%~12%的含油量,添加麦芽糊精、大豆分离蛋白和CMC可降低壳层5%左右的含油量,而谷朊粉、HPMC和瓜尔胶则可降低壳层1%的吸油量。添加0.2%、0.5%和1%的鱼鳞胶原蛋白可以降低油炸壳层1%~2%的吸油量,且添加1%鱼鳞胶原蛋白壳层的吸油量降低最多,而添加2%、5%和7.5%的鱼鳞胶原蛋白增加了油炸壳层的吸油量。2%与7.5%的鱼鳞胶原蛋白可改善油炸壳层和微波复热壳层的脆性。      

油炸食品吸油过程的机制分析

以油炸冷冻土豆条为研究对象,研究了油炸过程和冷却过程中,样品表面温度和内部温度的变化,以及因温度变化引起的蒸汽压力的变化。测量数据表明:在油炸过程中,食品的内部温度升至水的沸点后不再增加,食品的表面温度很快升至比油温低20～30℃左右就不再变化;在冷却过程中,食品的表面温度很快下降;而食品内部温度降低较慢。对吸油的两种驱动机制进行了比较分析,最终确定毛细吸力对吸油的影响较小,大部分的吸油是因为食品内水蒸汽冷凝而带来的表面壳层孔洞内外压力差而导致的。     

Effects of Rice Batter on Oil Uptake and Sensory Quality of Coated Fried Okra

ABSTRACT: Okra was coated and deep-fat fried with batters of flour sources including rice flour, a mixture of rice flour and small amounts of pregelatinized rice flour (PGRF), and, as a control, traditional wheat flour. The addition of PGRF, up to 8%, enhanced batter viscosity and the coating properties of the rice batter. Oil uptake of the fried batter decreased with the addition of up to 5% PGRF. Rice flour fried batters, with and without PGRF, were found to absorb substantially lower oil, by as much as 51 %, compared with the wheat batter. The fried okra coated with the rice batter containing 5% PGRF, when evaluated for sensory properties on appearance and surface attributes, was found to be superior or equal to those with the wheat batter and rice batter without PGRF. Particularly, its golden brown color is considered more desirable than the lighter yellow color of the other 2 entities. Similarly, most of its 1st-bite and after-chew properties were slightly better and were in the normal range of commercially available products. Specifically, its distinctive crispiness is considered a positive attribute, whereas its slightly higher tooth packing properties, while remaining in the range of commercial products, may be noticeable to some consumers.     

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。     

煎炸花生油中的总极性组分对脂质代谢的影响

花生油在煎炸过程中发生一系列化学反应,产生了氧化甘油三酯、聚合甘油三酯和游离脂肪酸等极性大于甘油三酯的极性组分。用煎炸花生油的极性组分处理人肝癌细胞(HepG2),通过油红染色评估细胞内脂肪的含量,通过RT-PCR测量与脂质合成密切相关的基因(SREBP-1c、FAS、ACC、HMGCR)的mRNA相对表达含量评估脂质代谢情况。结果表明:随着极性组分的增多,细胞内脂肪含量明显增多;在极性组分质量浓度为2. 0 mg/mL时,SREBP-1c、FAS、ACC的mRNA水平分别增加为对照组的2. 95±0. 08(P 0. 05)、3. 24±0. 16(P 0. 05)、1. 77±0. 18(P 0. 05)倍,表明花生油中的极性组分会上调脂质合成相关基因的表达,进而导致HepG2细胞的脂质聚积。研究结果说明煎炸花生油中的极性组分在细胞层面导致脂质代谢紊乱。     

Reduction of oil uptake of fried food by coatings: A review

Fried food is popular because of its attractive aroma, colour and taste. However, its high oil content may cause cardiovascular diseases, such as high cholesterol and high blood pressure. Therefore, it is of great significance to reduce the oil uptake of fried food. It is found that water-oil replacement, surfactant theory and the cooling-phase effect are the main mechanisms of oil uptake in fried food. According to these mechanisms, improving the frying technology, changing the frying medium and coating treatment can reduce the amount of oil in fried foods. Among these methods, coating treatment is the most common method to reduce the oil content. Protein coatings usually have better performance than polysaccharide coatings. The performance of protein coatings depends on the type of food and protein. In addition, oil resistance of protein coatings can be improved by adding the plasticiser, combination with other components and cross-linking treatment.     

Effects of cross-linked tapioca starches on batter viscosity and oil absorption in deep-fried breaded chicken strips

In this study, the effectiveness and feasibility of using various degrees of cross-linked tapioca starches in batter and breading formulations to reduce oil absorptions in deep fried chickens were investigated. Shear flow behaviour, water retention capacity (WRC), pick-up as well as cooked yield of the prepared batters were also examined. Flow curves showed that all studied batters were pseudoplastic, i.e. having shear thinning characteristics. In addition, it was found that the substitution of 20% (w/w) cross-linked starches for wheat flour in the batter formulation significantly reduced the consistency index and WRC of the batters. However, batter pick-up and cooked yield values were insignificantly affected. Oil uptake of fried chicken crusts was determined using differential scanning calorimetry due to its specific advantages over the conventional solvent extraction method. In comparison to the control (wheat) formulation, crusts of fried chicken samples obtained from the formulations containing 20% (w/w) cross-linked starch showed significantly lower oil content by at least 17% relative oil reduction. The highest relative oil reduction was found in the batter containing the highly cross-linked tapioca starch. Furthermore, an increase in water content in the batter formulations resulted in a reduction in the batter pick-up, cooked yield and oil absorption. The degree of cross-linking which in turn resulted in the limited starch granule disintegration is the predominant factor in the reduction of oil content for deep-fried battered food.     

Understanding the texture of low moisture cereal products: mechanical and sensory measurements of crispness

The texture of extruded starch products has been measured sensorially and instrumentally. The instrumental data were analyzed using different approaches such as fractal analysis and peak analysis. The data showed useful correlations between sensory crispness and crackliness and a parameter obtained from the application of a newly developed fractal method to analyze the force deformation curve obtained from a penetration test of the cereal samples. This suggests that fractal analysis of the force‐deformation plots could be used instead of sensory analysis. Moreover, it was observed that an increase in water content altered the texture of starch based samples from crispy to crackly, whereas the texture of starch‐sucrose samples remained unchanged in the same hydration range. © 2000 Society of Chemical Industry     

Relationship between total polar components and polycyclic aromatic hydrocarbons in fried edible oil

ABSTRACT

Deep-fried dough sticks (a Chinese traditional breakfast) were fried individually in peanut, sunflower, rapeseed, rice bran, soybean and palm oil without any time lag for 32 h (64 batches fried, each for 30 min) and fried oil samples were obtained every 2 h. The frying-induced changes in the levels of total polar compounds (TPC) and polycyclic aromatic hydrocarbons (PAHs) were investigated by edible oil polar compounds (EOPC) fast separation chromatographic system and gas chromatography-mass spectrometry (GC-MS), respectively. The correlations were analysed of TPC with benzo[a]pyrene (BaP), TPC and PAH4 (benzo[a]anthracene, chrysene, benzo[b]fluoranthene and benzo[a]pyrene) as well as TPC with PAH16 (USEPA 16 PAHs). The results revealed that the levels of TPC and PAHs in fried oil considerably increased with frying time, and the type of oil affected their formation, which could inform the choice of oil for frying. The total BaP equivalents (∑BaPeq) concentrations in fresh oil and in oil whose TPC exceeded 27% were 2.14–13.48 and 5.78–10.80 μg kg^–1, respectively, which means that the carcinogenic potency of frying oil was more pronounced than that of fresh oil. In addition, the TPC concentration was significantly correlated with the concentrations of the sum of the 16 PAHs, PAH4 and BaP, so that the levels of PAHs could be predicted according to the levels of TPC in fried oil. In European standards, the rejection point for TPC in frying oil should be recalculated when considered PAHs. In all, the concentration of PAHs is a vital factor for ensuring the safety of frying oil.     

芝麻油香气成分研究

芝麻油的香气成分是吡嗪、呋喃、噻唑、噻吩、吡咯,以及醇、醛、酮、酸、酯类等化合物。用葡萄糖、半胱氨酸、精氨酸和水解芝麻蛋白,在145℃下加热40 m in,可以产生接近焙炒芝麻的香气,香气中的主要物质是2-乙基-5-甲基吡嗪、乙酰呋喃、2-乙酰噻唑和5-乙基-4-甲基噻唑。这些香气成分沸点低,因此芝麻香油不适于煎炸,而且生产芝麻香油温度过高,会引起诸多营养物质劣变,将影响芝麻的资源利用。机榨、低温压榨和水酶法制取的芝麻油,油品用途广,并能综合开发蛋白质、维生素和芝麻木酚素等营养成分。     

山稻米糠油营养成分分析与比较

分别对江南地区栽培较广的3个山稻品种进行了米糠含油率、脂肪酸组成、不皂化物含量与组成、γ-谷维素含量的分析,并与水稻和旱稻米糠油进行对比。结果表明,3个山稻品种米糠含油率均高于水稻和旱稻,最高的是山稻18号,含油率达(23.08±2.20)%;脂肪酸组成最丰富的是山稻14号,共检出14种脂肪酸,必需脂肪酸质量分数最高的是山稻5号,仅次于旱稻,达35.83%,最低的是14号,为28.31%;米糠油不皂化物中含量最高的是甾醇类化合物,3个山稻品种中植物甾醇质量分数均超过总不皂化物的50%;山稻18号角鲨烯含量最高,仅次于旱稻,达1 168.91mg/kg; 5种米糠油中γ-谷维素含量从高到底分别为山稻18号、山稻5号、旱稻、山稻14号和水稻,γ-谷维素质量分数分别为(20.74±0.08)、(18.26±0.08)、(16.68±0.88)、(14.72±0.31)、(12.61±0.11) mg/g, 5个品种间γ-谷维素含量差异极显著(P<0.01)。山稻米糠含油率较高,脂肪酸组成丰富,油中植物甾醇和γ-谷维素等含量均高于传统栽培的水稻和旱稻,是一种极具潜力的食用油。     

不同温度处理的大豆分离蛋白乳化大豆油对猪肉糜品质的影响

目的 探讨应用不同温度（20 ℃、60℃和98℃）处理的大豆分离蛋白乳化大豆油替代猪背膘生产低脂猪肉糜的可行性。方法 测量猪肉糜的色泽、质构、保水性、水分分布和移动性。结果 添加不同温度处理的大豆分离蛋白乳化大豆油显著提高（P < 0.05）猪肉糜的L*和b*值、蒸煮得率、硬度、弹性、内聚性和咀嚼性,降低水分移动性。大豆分离蛋白处理温度显著影响猪肉糜的品质,添加98℃处理大豆分离蛋白乳化大豆油的猪肉糜有最高的（P < 0.05）L*和b*值、蒸煮得率、质构特性和不易流动水的含量。结论 添加98℃处理大豆分离蛋白乳化大豆油的猪肉糜品质最佳。     

Technological and functional properties of reduced-salt pork batter incorporated with soy protein isolate after pressure treatment

To investigate the effects of different pressures (0.1–400 MPa), the techno-functional properties, water distribution and mobility of reduced-salt pork batters (1% NaCl) supplemented with soy protein isolate (SPI, 2%) were examined. Compared with the batters treated at 0.1 MPa, those treated at 100–300 MPa showed significantly increased the cooking yield, hardness, springiness, cohesiveness, chewiness, and G′ values of gel and reduced the initial relaxation times of T_2b, T₂₁ and T₂₂, as observed from the results of low-field NMR. Among all samples, those treated at 200 and 300 MPa had the highest L^* value, cooking yield, hardness, springiness, cohesiveness, chewiness and G′ value of gel, with the largest peak ratio of P₂₁ and the smallest peak ratio of P₂₂. Overall, treatments at 200 and 300 MPa improved the gel properties and lowered the water mobility of reduced-salt pork batters supplemented with SPI.     

A different perspective to study the effect of freeze, air, and osmotic drying on oil absorption during potato frying

ABSTRACT:  The objective of this article is to assess the effect of different dehydration pretreatments on oil absorption and illustrate how the different ways results can be reported may even drive to opposite conclusions. To do so, potato cylinders were blanched in hot water and dried until a moisture content of 62% (w.b.) by either freeze-drying, air drying, and osmotic drying with a sucrose solution or osmotic drying with a NaCl solution. Control (blanched) and dried potatoes were deep-fat fried at 170 °C for time periods between 1 and 5 min. Water removal and total oil uptake were determined and 2 oil fractions were distinguished: superficial oil and penetrated oil. Compared to the control, freeze dried samples increased oil uptake in 15.4% (d.b.) whereas air-dried samples reduced it in 11.2% (d.b.). Similarly, osmotic dehydrated samples showed a high reduction in oil uptake compared to the control (up to 27%[d.b.] when using a sucrose solution). However, this high decrease in oil absorption was attributed to the increase in solids content occurring during the osmotic dehydration process rather than a reduction in the amount of oil taken up. In fact, when the amount of oil absorbed per cylinder was determined, it was verified that oil uptake of osmotically dehydrated samples was even higher than the control, as opposed to what has been previously reported in the literature. These results highlight the importance of selecting an adequate basis to carry out comparisons properly.     

4种功能性低聚糖对海绵蛋糕的面糊性能和烘焙品质的影响

针对海绵蛋糕的高糖问题,选用4种功能性低聚糖完全替代海绵蛋糕中的蔗糖,分别比较了它们对海绵蛋糕的面糊性能和烘焙品质的影响。结果表明:低聚异麦芽糖、低聚果糖、低聚半乳糖的面糊性能与蔗糖组较为接近,显示出良好的替代性,使用这3种糖制作的海绵蛋糕贮藏3d后依然是可接受的。而菊粉因为吸湿性极强,其海绵蛋糕成品比容小,硬度大,咀嚼时粉质感强烈,可接受度最低。