PRESSURE CONDITIONS AND QUALITY OF CHICKEN NUGGETS FRIED UNDER GASEOUS NITROGEN ATMOSPHERE

The potential for using nitrogen gas as a pressurizing medium in a deep‐fat fryer was investigated. Effects of different frying temperatures (150, 175 and 190C) and pressures (101, 163 and 184 kPa) on the fried food quality were studied. Chicken nuggets were either fried for a constant frying time of 240 s or at a constant core temperature of 70C in a modified restaurant‐type pressure fryer. Modifications were made to include external gases to pressurize the frying chamber. The quality characteristics of the fried products were determined. An increase in pressure applied during frying resulted in tender and juicier fried products because of the reduction in moisture loss. The increase in pressure reduced oil uptake by the fried products. Compared with the use of steam released from the food, frying under nitrogen gas provided similar or better quality of fried products in terms of moisture retention, juiciness and texture.     

Functionality of batters containing different starch types for deep-fat frying of chicken nuggets

The effect of various starch types (amylomaize, corn, waxymaize, pregelatinized tapioca) on quality attributes (texture, moisture content, oil content, color, coating pick up, cooking yield, volume and porosity) of deep-fat fried chicken nuggets were studied. Chicken samples, 0.04 m in diameter and 0.015 m in thickness, taken from the breast portion, were coated with batters composed of a 3:5 solid to water ratio by immersion. The solid content of batter formulations contained equal amounts of corn and wheat flour, 5.0% starch, 1.0% salt and 0.5% leavening agent. As control, batter without starch addition, was used. Samples were fried at 180°C for 3, 6, 9 and 12 minutes. Crispness and oil content of chicken nuggets increased, whereas moisture content decreased with increasing frying time. Starch addition to the formulations increased crispness of the product significantly at the last stages of frying. The highest porosity and oil content was obtained when corn starch was used. Pregelatinized tapioca starch was found to provide a product with the lowest oil content, the highest moisture content, coating pick up and volume.     

Effects of batters containing different protein types on the quality of deep-fat-fried chicken nuggets

The effects of soy protein isolate (SPI), whey protein isolate (WPI) and egg albumen (EA) on the quality of deep-fat-fried chicken nuggets were studied. Batter without protein addition was used as a control. Batter pickup and moisture content, oil content, texture, porosity and colour of the nuggets were determined for 3, 6, 9 and 12 min of frying at 180 °C. Additionally, the rheological properties of batters were studied. SPI (3%) provided the highest apparent viscosity and coating pickup. All the batters showed shear-thinning behaviour except EA-added batter. Addition of different proteins to the batter formulation decreased the oil content of the final product. EA reduced the oil content of chicken nuggets significantly but yielded softer products. WPI (3%) was found to be the most effective ingredient on improving quality parameters of deep-fat-fried chicken nuggets. WPI (3%) added batters provided the hardest and crunchiest product with the darkest colour and also significantly reduced the oil content of the fried nuggets.     

油炸温度和时间对猪肉块品质的影响

本文研究了不同油炸温度和时间对猪肉块品质的影响,分析了150、165和180℃条件下油炸不同时间后猪肉块的色泽、硬度、水分含量、脂肪含量、蛋白质羰基含量、硫代巴比妥酸值(TBARS值)和挥发性醛类物质的变化情况。实验结果表明,油炸后猪肉块的亮度降低,红度和黄度升高;硬度在油炸过程中变化显著(p<0.05),150℃油炸470 s时达到最大值37.59 kg;150、165和180℃分别油炸470、330和230 s后猪肉块的水分含量减少了56.25%、52.82%和48.92%(p<0.05),高温短时油炸条件下水分损失较少;脂肪含量在150、165℃时随时间变化不显著,180℃油炸时随时间的延长显著增加(p<0.05);蛋白质羰基含量随油炸时间的延长而增大,180℃油炸150 s时猪肉块的蛋白质羰基含量为2.17 nmol/mg;TBARS值和己醛含量在油炸后迅速增大,之后呈现先减小后均大的趋势,180℃油炸150 s的TBARS值为0.71 mg MDA/kg;挥发性醛类物质中己醛与TBARS值相关性显著,150、180℃条件下的相关系数分别为0.962和0.997。180℃油炸150 s时的猪肉块具有金黄的色泽,硬度适中,脂肪和蛋白质氧化程度较小,具有较好的品质。     

稻米油调和油煎炸应用研究

通过与棕榈油对比180℃下炸制薯片以及评估薯片感官喜好度、质构、口感及粘牙性等差异来评价稻米油调和油的煎炸应用性能。结果表明:采用稻米油调和油煎炸的薯片中多不饱和脂肪酸含量显著高于棕榈油(P<0.05),且其薯片的整体感官喜好度、质构口感、酥脆度、粘牙喜好度,均显著优于棕榈油薯片(P<0.05)。在加速氧化条件下,采用稻米油调和油炸制的薯片的酸价、过氧化值均与棕榈油炸制的薯片无显著性差异(P>0.05),且远低于GB 16565-2003的规定。在加速存储过程中,谷维素却得到了很好的保留。总之,稻米油调和油具有良好的煎炸性能。     

Porosity determination of deep‐fat‐fried coatings using pycnometer (Fried batter porosity determination by pycnometer)

The effect of processing conditions such as frying time and temperature, and batter formulation on pore development in deep‐fat fried chicken nuggets coatings were studied using helium pycnometer method. Chicken nuggets with preformed and laboratory prepared batter coatings were fried at temperatures between 170 and 190 °C for a time range between 0 and 240 s. There was significant (P < 0.05) effect of frying temperature and batter formulation on porosity. Porosity increased with frying time and temperature, and ranged between 2.15 and 47.92% for the preformed batter and 9.96 and 54.76% for the formulated batters. Apparent and bulk densities of the preformed batters increased and decreased with frying time, respectively, but both declined gradually with increasing frying temperature. As the level of rice flour in the formulation increased, apparent and bulk densities also increased. Batter formulation and frying temperature significantly (P < 0.05) influenced the variation in moisture and fat content of the fried batter. Porosity demonstrated positive and negative correlation with fat uptake and moisture loss, respectively, for all the batter coatings.     

COMPARISON OF BATTER-BREADED BEEF NUGGETS DEEP-FRIED IN COTTONSEED AND SOYBEAN OILS AND LIQUID SHORTENINGS

Restructured beef nuggets were batter-breaded and deep-fried in commercial cottonseed oil (CO), cottonseed liquid shortening (CLS), soybean oil (SO) and soybean liquid shortening (SLS) and stored at 4C for 0 or 4 days. Weight losses during frying and reheating were not significantly influenced by the frying medium used. No major sensory differences were noted among the different products except that, on day-0, nuggets fried in SLS had a "slight" warmed-over flavor due to the reversion flavor of the frying medium itself. On day-0, nuggets fried in CO or CLS had lower TBA values than those fried in SO or SLS. However, on day-4, nuggets fried in CLS or SLS had lower TBA values than nuggets fried in CO or SO. CLS may be the frying medium of choice among the four because of its ability to resist lipid oxidation in both fresh fried and stored nuggets.     

The Effect of Food Type (Fish Nuggets or French Fries) on Oil Blend Degradation during Repeated Frying

Abstract: Oil that is reused multiple times for deep frying goes through changes in chemical composition and physical characteristics, affecting the quality of the fried foods. In this study, the effect of the food type (fish nuggets or French fries) on the degradation of an oil blend during the deep‐fat frying of each food at 180°C during 12 days was determined, and the characteristics of the fried products were evaluated. The degradation of oil during repeated use was relatively faster when fish nuggets were fried than when French fries were fried, as higher values of total polar compounds were obtained. Practical Application: The results are useful for producers of French fries and fish nuggets, such as restaurants or fast foods sellers, providing them with practical guidelines within the permitted values established by the regulatory authorities. The studied foods have high economic importance and are different in their composition. Under the studied conditions, the tested oil blend may be used during 4 d (4 h per day) with a daily replenishment, without discarding the oil when frying fish nuggets, and must be discarded after 8 d when French fries are processed. This suggestion allows preparing safe fried foods for consumers.     

QUALITY OF NUGGETS PREPARED FROM FRESH AND SMOKED SPENT LAYER CHICKEN MEAT

Nuggets were prepared from fresh and smoked meats of spent layer chicken of age approximately 18 months, packed in polyethylene bags and stored at -18 ± 2C for 6 months. Thawed nuggets were fried on hot pan coated with refined sunflower oil and product quality was evaluated. Nuggets from smoked chicken had lower (P ± 0.05) moisture and higher fat contents and lower weight loss on frying compared to fresh meat nuggets. Free fatty acid (FFA expressed as percent of oleic acid) increased from 3.6 to 3.9 and 3.2 to 3.7, and thiobarbituric acid (TBA) values (mg malonaldehyde/kg sample) increased from 0.90 to 1.19 and 0.63 to 0.71 for fresh and smoked meat nuggets, respectively, during frozen storage for 6 months. Shrinkage in product diameter on frying ranged from 4.6 to 5.0%. Warner-Bratzler shear values ranged from 0.89 to 1.28 lbs for all products stored frozen up to 6 months. Sensory quality scores for smoked meat nuggets were significantly (P ± 0.05) higher, except for juiciness (P ≥ 0.05), than for fresh meat nuggets. Smoked chicken meat produced better nugget products compared to fresh meat as indicated by lower FFA and TBA values and better sensory quality attributes. Products packed in polyethylene bags can be stored at -18 ≥ 2C for up to 6 months without marked deterioration in product quality.     

Enhancement of Frying Oil Stability by a Natural Antioxidative Ingredient in the Coating System of Fried Meat Nuggets

Cottonseed oil containing commercial antioxidants was used for continuous (a 2-day time period; < 24 hr) frying of beef nuggets that were batter-breaded with either 100% commercial coating mix or a coating system containing defatted glandless cottonseed flour (GCF). Analyses of oil samples revealed that oil used for frying the nuggets with the GCF-containing coating was less susceptible to lipid hydrolysis and oxidation and color-darkening. GCF in the coating also minimized lipid oxidation in beef nuggets fried in the oil at various stages of heating time during the 2-day frying operation. Results indicated that GCF in the coating not only could enhance the oxidative stability of fried nuggets but also could decrease the breakdown of the frying oil.     

The performance of a methyl cellulose-treated coating during the frying of a poultry product

The performance of coatings treated with a range of methyl cellulose (MC) concentrations during the frying of coated chicken breasts was investigated. Chicken breasts were immersed in 0, 1 and 2.5% MC solution and then coated with a commercial coating mix. The coated chicken breasts were then fried at an initial temperature of 190 °C. Parameters measured included coating pickup, coating loss, cooked yield and frying loss. Results showed a significant increase in coating pickup with the use of 1 and 2.5% MC, which may have been due to the higher viscosity and binding ability of the MC layer. The use of 2.5% MC produced lower coating loss and frying loss and also a higher cooked yield.     

Effect of superheated steam prefrying treatment on the quality of potato chips

Superheated steam drying (SSD) was used as a prefrying treatment prior to deep‐fat frying for potato slices. The effect of SSD at 130, 150 or 180 °C and steam velocity of 2.0 m s^?1 on the fat uptake, colour and texture of fried potato chips was evaluated; microstructure and degree of starch gelatinization were also evaluated to help explain the fat uptake results. SSD and frying yielded potato chips with the fat content from 0.263 ± 0.002 to 0.304 ± 0.002 kg kg^?1 (d.b.), while frying without SSD led to chips with the fat content as high as 0.359 ± 0.003 kg kg^?1 (d.b.). SSD did not promote starch gelatinization. Lower fat uptake was correlated to modified surface structure and lower moisture content of potato slices prior to frying. Frying with/without SSD pretreatment yielded potato chips of similar hardness, crispness and lightness. On the other hand, SSD significantly increased redness and yellowness of the fried chips.     

Comparative evaluation of edible coatings to reduce fat uptake in a deep-fried cereal product

Eleven hydrocolloid materials including gelatine, gellan gum, κ-carrageenan-konjac-blend, locust bean gum, methyl cellulose (MC), microcrystalline cellulose, pectin (three types), sodium caseinate, soy protein isolate (SPI), vital wheat gluten and whey protein isolate (WPI) were compared for their film forming ability, suitability for fried foods, and water and fat transfer properties. Various selected formulations and preparation methods were investigated for their effectiveness, and for their heat stability on a product made from a pastry-mix. Gelatine, wheat gluten and sodium caseinate were not suitable in single material coating. The SPI, WPI and MC were the best materials for coating to reduce fat uptake during frying. Composite films of two to three materials in multiple coatings or a single coating with mixed materials were also evaluated. Multiple coatings provided large film thicknesses. SPI/MC and SPI/WPI mixed coatings provided the highest index value (reduction in fat uptake/decrease of water loss), and reduced the fat uptake up to 99.8%.     

Effects of batters containing different gum types on the quality of deep‐fat fried chicken nuggets

The effects of various gum types [hydroxypropylmethylcellulose (HPMC), guar gum, xanthan gum, gum arabic] on the quality of deep‐fat fried chicken nuggets were studied. Chicken samples, 0.04 m in diameter and 0.015 m in thickness taken from the breast portion, were coated with batters composed of a 3:5 solid to water ratio by immersion. The solid content of batter formulations contained equal amounts of corn and wheat flours, 1.0% gum, 1.0% salt and 0.5% leavening agent. As control, batter without gum addition was used. Samples were fried at 180 °C for 3, 6, 9 and 12 min. The hardness and oil content of the chicken nuggets increased whereas the moisture content decreased during frying. HPMC and xanthan gums reduced oil absorption significantly compared with other gums and the control. When gum arabic was added to the batter formulation, a product with the highest oil content and porosity was obtained. Copyright © 2005 Society of Chemical Industry     

Application of pretreatment methods on agricultural products prior to frying: a review

Frying is one of the methods of processing foods, which imparts flavour, taste, colour and crispness in the fried foods. In spite of an increase in the demand for fried foods by consumers all over the world, the danger posed by consuming too much fat is still a challenge. Many researchers have put forward many ideas on how to reduce the oil uptake and improve the nutritional and organoleptic qualities of foods during frying. Several pretreatment techniques applied to food materials prior to frying have been investigated by researchers in a bid to reduce the oil uptake and improve the quality parameters of fried foods. Therefore, this review focuses on the various pretreatment methods and the recent novel methods like ultrasound, infrared, superheated steam drying, microwave technique and pulsed electric field applied to foods prior to frying and its effects on the qualities of fried foods. © 2017 Society of Chemical Industry     

Reviewing the effects of vacuum frying on frying medium and fried foods properties

Vacuum frying (VF) is a process developed at a pressure lower than atmospheric pressure, in which lower temperatures are employed to remove moisture from the food and reduce the oil content in the final product. Diverse studies have been published for VF or assisted with microwave and ultrasound, facing the challenges of accomplishing the physical and sensory properties appreciated in fried products. The studied matrices under VF include mainly vegetable origin foods (apple, banana, carrot, donuts, kiwi, mushroom, pea, pear, potato and sweet potato) and some animal origin products (chicken nuggets, fish fillets and surimi products). This review aimed to show recent and relevant findings of the application of VF, analysing both the effects on the frying medium and the impact on the fried foods. The inclusion of microwave and ultrasound technologies aids in the obtention of high-quality products in terms of sensory and textural attributes, oil content as well as reduced oil degradation. This technique may provide safer and stable fried foods with lower oil content aiding in improving the diet of consumers and reducing production costs.     

Quality changes in mixtures of hydrogenated and non‐hydrogenated oils during frying

BACKGROUND: There is a need for frying oils with reduced trans fatty acid content and increased oxidative stability. This study was conducted to measure and compare frying oil quality parameters, namely colour, viscosity, free fatty acid (FFA) content and dielectric property, and to investigate changes in properties of mixtures of fully hydrogenated and non‐hydrogenated canola oils during deep‐fat frying of chicken nuggets. Proportions of hydrogenated oil to non‐hydrogenated oil used in the study were 0, 20, 40, 60, 80 and 100%. Chicken nuggets were fried at 190 °C. The relationships among quality parameters, frying time and oil type were investigated. RESULTS: Frying time and oil type had significant effects on all properties. First‐order kinetic equations were used to represent changes in colour, viscosity and FFA content. The rates of change of viscosity and FFA content were higher in non‐hydrogenated oil, whereas the rates of change of colour were similar in the different oils. Increasing the level of hydrogenated oil in the mixture resulted in only slight changes in quality parameters. CONCLUSION: Quality parameters, namely colour, viscosity, FFA content and dielectric property, of frying oil are significantly affected by frying time and hydrogenation level. Frying oil quality and stability can be adjusted by mixing hydrogenated and non‐hydrogenated oils. Copyright © 2008 Society of Chemical Industry     

Effect of Osmotic Dehydration and Vacuum-Frying Parameters to Produce High-Quality Mango Chips

ABSTRACT:  Mango ( Mangifera indica  L.) is a fruit rich in flavor and nutritional values, which is an excellent candidate for producing chips. The objective of this study was to develop high-quality mango chips using vacuum frying. Mango (" Tommy Atkins ") slices were pretreated with different maltodextrin concentrations (40, 50, and 65, w/v), osmotic dehydration times (45, 60, and 70 min), and solution temperatures (22 and 40 °C). Pretreated slices were vacuum fried at 120, 130, and 138 °C and product quality attributes (oil content, texture, color, carotenoid content) determined. The effect of frying temperatures at optimum osmotic dehydration times (65 [w/v] at 40 °C) was assessed. All samples were acceptable (scores > 5) to consumer panelists. The best mango chips were those pretreated with 65 (w/v) concentration for 60 min and vacuum fried at 120 °C. Mango chips under atmospheric frying had less carotenoid retention (32%) than those under vacuum frying (up to 65%). These results may help further optimize vacuum-frying processing of high-quality fruit-based snacks.     

Effects of frying temperature,pressure and time on gelatinisation of sago flour as compared to wheat and rice flour in fried coating

This study was conducted to determine the gelatinisation properties of coating with sago flour compared with wheat and rice as influenced by frying temperature, pressure and time. Chicken nuggets were immersed in sago, rice or wheat flour batters and fried at temperatures of 150, 165 and 180 °C and under pressures of 102 and 156 kPa for 0, 6, 18 and 30 s. Results showed that T_o of coatings from sago flour ranged from 71.8 to 74.7 °C. T_o of coatings from wheat flour ranged from 58.2 to 61.2 °C, while that of coatings from rice flour ranged from 77.9 to 78.6 °C. Except for a few combinations, frying temperature and pressure used did not have any significant effects on onset (T_o), peak (T_p) and end (T_e) temperatures. Except for a few combinations, degree of gelatinisation of coatings from sago flour was not influenced by frying temperature and pressure similar to coatings from rice and wheat flour.