Characteristics and oil absorption of deep‐fat fried dough prepared from ball‐milled wheat flour

BACKGROUND: High levels of oil in fried products has been recognized as causing health problems. The formation of microstructure during frying is one factor that influences oil absorption. Above the glass transition temperature (T_g), the physical properties of a polymer influences the formation of structure. The ball‐milling process changes the physicochemical properties of wheat flour constituents. The present study investigated the effects of physicochemical changes in wheat flour by the ball‐milling process on structure formation and oil absorption in wheat flour dough model. RESULTS: Dough samples were made from wheat flour that had been ball‐milled for 0 to 10 h and then fried in frying oil at 150 °C for 1–7 min. Thermal properties of wheat flour, structure alteration, and textural properties of fried samples were evaluated. As compared with samples made of non‐milled flour, samples made from milled flour had smaller pores and higher oil absorption. The fracture force of a fried sample prepared from non‐milled flour was lower than that of a sample prepared from milled flour. CONCLUSION: Ball‐milling affected the microstructure formation in fried wheat flour dough, and subsequently oil absorption. The crispness of a sample prepared from non‐milled wheat flour is higher than that of a sample prepared from ball‐milled wheat flour. This may be due not only to a plasticization effect, but may also be dependent on microstructure. Copyright © 2008 Society of Chemical Industry     

Effects of ball‐milling on the glass transition of wheat flour constituents

BACKGROUND: Starch and gluten, the major components of wheat flour, greatly influence the structural characteristics of food products made with wheat flour. The effects of ball‐milling on the change in the semicrystalline structure of starch granules to the amorphous state have been reported. However, the effects of ball‐milling of native wheat flour on physicochemical changes in wheat flour constituents have not been elucidated. Therefore in this study the effects of ball‐milling on the glass transition of wheat flour constituents were investigated. RESULTS: Crude gluten, non‐gluten proteins and separated starch were obtained from wheat flour ball‐milled for 0–10 h, and the glass transition temperature (T_g) of these constituents was evaluated. The T_g of all wheat flour constituents decreased with increasing ball‐milling time. Sodium dodecyl sulfate polyacrylamide gel electrophoresis revealed that changes in band position and intensity did not occur for gluten but did occur for non‐gluten proteins. X‐ray diffraction revealed decreased crystallinity and greater plasticisation by water in separated starch as the ball‐milling time was prolonged. CONCLUSION: The results showed that the ball‐milling process decreased the T_g of wheat flour constituents as a function of milling time. The decrease in T_g was probably due to changes in conformation of protein subunits in gluten and depolymerisation of the non‐gluten protein fraction. The information obtained here about the physical alteration of wheat flour constituents may enhance the ability to successfully use ball‐milled wheat flour in food applications. Copyright © 2008 Society of Chemical Industry     

Effects of deep‐fat frying temperature on antioxidant properties of whole wheat doughnuts

The total phenolic (TP) content, phenolic acid composition and in vitro antioxidant capacity of whole wheat doughnuts fried at 120–180 °C were determined to identify the effects of frying temperature. Significant differences (P < 0.05) in TP content were observed between doughnuts fried at different temperatures. The TP content of doughnuts decreased significantly when doughnuts were deep‐fat fried. The TP content of doughnuts increased with elevation with frying temperatures. These increases in TP content of doughnuts were also detected in the determination of individual phenolic compounds using HPLC. DPPH radical and iron‐chelating capacity of deep‐fat fried doughnuts exhibited increases with elevation of frying temperature from 120 to 180 °C. Deep‐fat frying at 120 °C lowered lipid peroxidation inhibition capacity of doughnuts prepared from both refined flour and whole‐grain meals and increased consistently with increased frying temperature from 120 to 180 °C. Moderate deep‐fat frying temperature would increase the content and activity of antioxidants of doughnuts.     

Fractionation and characterization of ball‐milled and enzyme lignins from abaca fibre

An Erratum has been published for this article in Journal of the Science of Food and Agriculture 79(15) 1999, 2122. Ball‐milled and enzyme lignins were produced from abaca fibre via ball milling for 6 days followed by cellulase treatment for 3 days. The crude lignin preparations were fractionated into milled lignin (ML), enzyme lignin (EL), hemicellulose‐rich milled lignin (HRML), and lignin‐rich enzyme lignin (LREL) fractions using a two‐step precipitation method instead of a traditional ether precipitation procedure. The yield and chemical composition of the resulting lignin samples are reported. The ML and EL fractions contained low amounts of associated neutral sugars (2.0–3.3%) and uronic acids (1.4–1.5%), and showed relatively low average molecular weights (2500–2660), while the LREL and HRML fractions contained large amounts of bound polysaccharides (35.6–38.3%), and showed high molecular weights (8800–25000). The four lignin fractions are composed of a large proportion of syringyl units with fewer guaiacyl and p‐hydroxyphenyl units. The ML is mainly composed of β–O–4 ether bonds between the lignin structural units. The less common β–β, β–5 and 5–5′ carbon–carbon linkages are also present in the lignin molecules. It was found that uronic acids and 41–63% of p‐coumaric acids are esterified to lignin in the three lignin‐rich fractions of ML, EL and LREL. This level increased to over 90% in the hemicellulose‐rich fraction of HRML. For ferulic acids, 92–97% were found to be etherified to lignin in the three lignin‐rich fractions of ML, EL and LREL, while in the hemicellulose‐rich fraction of HRML this reduced to only 13%, suggesting that a majority of the ferulic acids are esterified to hemicelluloses or lignin in this fraction. © 1999 Society of Chemical Industry     

Development and application of soy‐protein films to reduce fat intake in deep‐fried foods

A soy protein film coating was developed and evaluated to reduce fat transfer in deep‐fried foods during frying. Soy protein isolate solutions (10% SPI) with 0.05% gellan gum as plasticizer cooled after being held at 80 °C for 20 min provided suitable films. There was a significant fat reduction (55.12 (±6.03)%db) between fried uncoated and coated discs of doughnut mix. The same films were used on potato fries. Some panellists observed a slight difference between the coated and uncoated fries but many preferred the coated fries over the uncoated ones. Penetration test on potato fries showed no significant difference between the texture of coated (SPI with gellan gum) and the uncoated fried samples. A solution of 10% SPI with 0.05% gellan gum is recommended for coating foods to reduce fat intake during deep‐fat frying. © 2000 Society of Chemical Industry     

Characterization of deep‐fat frying in a wheat flour–water mixture model using a state diagram

BACKGROUND: Crispness is an important characteristic to be controlled in deep‐fat fried products. The physical state of food polymers influences the development of cellular structure and textural qualities of fried food. Glassy state is believed to play an important role in the mechanical properties of low‐moisture food. Therefore, an understanding of the physicochemical phenomena in the development of fried food structure using a state diagram of the frying process is discussed. RESULTS: Wheat flour models containing 400 and 600 g kg^?1 initial moisture content were fried in frying oil at 150 °C for 1–7 min. Thermal properties of wheat flour, structure alteration and textural properties of fried samples were evaluated. The porous structure continuously enlarged when the sample was in the rubbery state. As the frying time was prolonged, the state of the product became glassy due to a decrease in water content, resulting in the ceasing of porous enlargement. Conclusion: The results revealed that physicochemical changes during frying influence the alteration of microstructure and quality of fried food, and the state diagram could be applied to explain the formation of microstructure during the frying process and used as a decision‐making tool to choose the proper conditions to provide desirable qualities in fried food. Copyright © 2007 Society of Chemical Industry     

A simplified method for extracting water‐extractable arabinoxylans from wheat flour

BACKGROUND: Water‐extractable arabinoxylan (WEAX) is a minor constituent of wheat grain which influences the properties of wheat dough and its end products while conferring numerous health benefits. Consequently, various applications have been proposed for it in foodstuffs. Fortification of food products with pure WEAX extracts represents a simple means to evaluate its effect in these systems. However, rapid methods to isolate relatively pure WEAX are not available. This study aimed to develop a rapid, technically simple means to extract relatively pure WEAX on a small scale. RESULTS: A simplified process was developed to extract WEAX from wheat flour. After heating, flour WEAX was extracted with water and starch was eliminated by digestion with amyloglucosidase. Most of the protein was removed by adsorption to bentonite and precipitation with 65% ethanol. The final product generated by the developed method consisted of 93 ± 4% arabinoxylan. The WEAX yield was 0.43 ± 0.02% (0.43 ± 0.02 g WEAX/100 g of starting flour) which is higher than that of other methods that generate WEAX of similar purity. CONCLUSION: This method provides a technically simple means to perform small‐scale isolation of WEAX that contains no detectable contaminating protein. This attribute renders it a preferred input for studies assessing the impact of WEAX fortification on food product quality. Copyright © 2008 Society of Chemical Industry     

Effects of pre‐emulsifying fat/oil on meat batter stability,texture and microstructure

The effects of pre‐emulsified beef fat and canola oil (CO) (25%) with Tween 80 (T‐80) or sodium caseinate (SC) were studied in beef meat batters prepared at three protein levels (9%, 12% and 15%). Raising meat protein level to 15% resulted in low emulsion stability of products prepared with CO. Using pre‐emulsified beef fat with Tween 80 (BF‐T80) showed significantly higher fat and water losses at all protein levels. There were no differences in fat and water losses between pre‐emulsified beef fat and CO when SC was used at the 9% and 12% protein levels compared to the controls (non pre‐emulsification). Light microscopy revealed fat globule coalescence in the CO meat batters prepared with 15% protein and BF‐T8 treatments, as well as formation of fat channels and more protein aggregation; both resulted in lower emulsion stability. Using SC to emulsify fat/oil produced a finer dispersion of fat globules compared to all the other treatments.     

Effect of surface roughness on post‐frying oil absorption in wheat flour and water food model

The effects of surface roughness and post‐fried cooling time on oil absorption were investigated for a food model comprised of various wheat flour and water mixtures. The models were prepared by varying the initial moisture contents as 400, 600 and 800 g kg^?1. The samples were then fried at 150 °C in palm olein oil for 5 min and then left to cool down for 0, 1, 3 or 6 min. Fractal analysis was used to evaluate the resulting surface roughness of samples fried for 5 min. The results revealed that the average fractal dimension increased as the sample's initial moisture was increased. The adhered oil on the surface decreased with cooling time; however, the absorbed oil increased. The surface roughness that is generated during frying causes the quantity of adhered oil to increase during the initial cooling stage. As cooling progresses, the surface oil is absorbed by the sample in proportion to the fractal dimension and the initial moisture content. Copyright © 2005 Society of Chemical Industry     

A finer screening of wheat cultivars based on comparison of the baking potential of whole‐grain flour and white flour

Between 2007 and 2009, 160 wheat samples were harvested at four growing locations in Quebec (Eastern Canada) and evaluated individually for their performance in whole‐grain bread (all grain fractions) and white bread prepared with a long‐fermentation process (3 h). Combination of results from both baking tests allowed the most complete evaluation of the gas retention capacity of wheat samples. Compared to cultivar and crop year, growing location had a minor effect on the overall bread making potential of wheat samples. In whole‐grain bread, the four winter wheat lines had a poorer performance than the twenty‐one spring wheat cultivars. Little correlation was seen between dough mixing stability and gas retention properties. Determination of strong gluten content (dry gluten × gluten index) might be a useful screening tool for early‐generation wheat cultivars.     

Effects of variety and stage of fruit ripeness on the physicochemical and sensory characteristics of deep‐fat‐fried banana chips

The quality of banana chips prepared from two different varieties of banana, Pisang Abu and Pisang Nangka, at the ‘green’ and ‘trace of yellow’ stages of ripeness was studied. The fruits were peeled, sliced to a thickness of 2 mm and deep‐fat fried in refined, bleached and deodorised (RBD) palm olein at 180 ± 5 °C for 3 min. The quality parameters determined for fresh bananas were total soluble solids, pH, acidity, carbohydrate, sugar content, fat, protein, moisture content, ash, fibre, colour and fruit firmness. The results showed that Abu had a higher carbohydrate content than Nangka at both stages of ripeness before frying. No sucrose was detected in Nangka. The quality parameters determined after deep‐fat frying were moisture content, water activity, oil absorption, crispness and sensory evaluation. The moisture content and water activity of Abu chips were lower than those of Nangka chips. The texture of chips prepared from Abu at stage ‘green’ showed more crispness than the other three samples. Sensory evaluation showed that chips prepared from Abu at both stages of ripeness presented better colour, flavour, odour, texture and overall acceptability than those prepared from Nangka. Based on the matrix of correlation coefficients, fresh bananas with higher fruit firmness and carbohydrate content gave banana chips with higher crispness and oil absorption. © 2001 Society of Chemical Industry     

Effects of type of packaging material on physicochemical and sensory characteristics of deep‐fat‐fried banana chips

A storage study of deep‐fat‐fried banana chips was carried out for 8 weeks at ambient temperature (27 °C), using four types of packaging material: laminated aluminium foil (LAF), oriented polypropylene (OPP), polypropylene (PP) and low‐density polyethylene (LDPE). The physicochemical and sensory characteristics of the stored banana chips were analysed at weeks 0, 2, 4, 6 and 8. The quality parameters determined were moisture content, water activity (a_w), thiobarbituric acid‐reactive substances (TBARS), texture (breaking force), colour and sensory attributes. The moisture content, a_w, TBARS and breaking force values of all samples increased during storage. The colour also changed during storage, showing higher L and lower a and b values. Samples packed in LAF had the lowest moisture content, a_w, TBARS and breaking force values. The most notable sensory change that occurred during storage was a decrease in crispness. Samples packed in LAF had higher scores than the other three samples, whilst LDPE gave the lowest scores for crispness as well as product colour. There were no significant differences (P > 0.05) in rancid odour among samples packed in OPP, PP and LDPE. However, there were significant differences (P < 0.05) between samples packed in LAF and the other three samples, with LAF giving the lowest rancid odour. © 2002 Society of Chemical Industry     

Influence of composition on degradation during repeated deep‐fat frying of binary and ternary blends of palm,sunflower and soybean oils with health‐optimised saturated‐to‐unsaturated fatty acid ratios

The American Heart Association recommended the fatty acid balance contributed by all the fats in our diet, suggesting it would be best at approximately 1:1:1 for saturated (SFA), monounsaturated (MUFA) and polyunsaturated fatty acids (PUFA), respectively. Three individual oils: palm oil (PO), soybean oil (SBO) and sunflower oil (SNF) and their binary and ternary blends were prepared and used for repeated deep‐fat frying of French fries. The acid value, peroxide value, p‐anisidine value and Totox values, as well as oxidative stability, contents of total polar compounds, tocochromanols, triacylglycerol dimers and oligomers, were determined in individual and blended oils. The lowest Totox value and highest stability were found for PO, and the opposite data were obtained for SNF and SBO. The degradation of tocochromanols in blends ranged from 91% to 95% after 4 days of frying, while in individual oils, it was 63% in SBO, 71% in SNF and 100% in PO. The lowest formation of dimers and oligomers was observed for the PO: SNF blend. Obtained results showed that only pure PO was a better frying medium than its blends with SBO and SNF. However, a prepared blend had a better fatty acid composition for human health and was more stable than pure SBO and SNF.     

Fish Protein Hydrolysates: Application in Deep‐Fried Food and Food Safety Analysis

Four different processes (enzymatic, microwave‐intensified enzymatic, chemical, and microwave‐intensified chemical) were used to produce fish protein hydrolysates (FPH) from Yellowtail Kingfish for food applications. In this study, the production yield and oil‐binding capacity of FPH produced from different processes were evaluated. Microwave intensification significantly increased the production yields of enzymatic process from 42% to 63%. It also increased the production yields of chemical process from 87% to 98%. The chemical process and microwave‐intensified chemical process produced the FPH with low oil‐binding capacity (8.66 g oil/g FPH and 6.25 g oil/g FPH), whereas the microwave‐intensified enzymatic process produced FPH with the highest oil‐binding capacity (16.4 g oil/g FPH). The FPH from the 4 processes were applied in the formulation of deep‐fried battered fish and deep‐fried fish cakes. The fat uptake of deep‐fried battered fish can be reduced significantly from about 7% to about 4.5% by replacing 1% (w/w) batter powder with FPH, and the fat uptake of deep‐fried fish cakes can be significantly reduced from about 11% to about 1% by replacing 1% (w/w) fish mince with FPH. Food safety tests of the FPH produced by these processes demonstrated that the maximum proportion of FPH that can be safely used in food formulation is 10%, due to its high content of histamine. This study demonstrates the value of FPH to the food industry and bridges the theoretical studies with the commercial applications of FPH.     

Fat digestion and absorption in spice‐pretreated rats

BACKGROUND: A few common spices are known to stimulate secretion of bile with higher amount of bile acids which play a major role in digestion and absorption of dietary lipids. It would be appropriate to verify if these spices enable efficient digestion and absorption during high‐fat intake. In this context, dietary ginger (0.05%), piperine (0.02%), capsaicin (0.015%), and curcumin (0.5%) were examined for their influence on bile secretion, digestive enzymes of pancreas and absorption of dietary fat in high‐fat (30%) fed Wistar rats for 8 weeks. RESULTS: These spices enhanced the activity of pancreatic lipase, amylase, trypsin and chymotrypsin by 22‐57%, 32‐51%, 63‐81% and 12‐38%, respectively. Dietary intake of spices along with high‐fat enhanced fat absorption. These dietary spices increased bile secretion with higher bile acid content. Stimulation of lipid mobilisation from adipose tissue was suggested by the decrease in perirenal adipose tissue weight by dietary capsaicin and piperine. This was also accompanied by prevention of the accumulation of triglyceride in liver and serum in high‐fat fed rats. Activities of key lipogenic enzymes in liver were reduced which was accompanied by an increased activity of hormone‐sensitive lipase. CONCLUSION: Thus, dietary ginger and other spice compounds enhance fat digestion and absorption in high‐fat fed situation through enhanced secretion of bile salts and a stimulation of the activity pancreatic lipase. At the same time, the energy expenditure is facilitated by these spices to prevent the accumulation of absorbed fat. Copyright © 2011 Society of Chemical Industry     

Quality characteristics of refined,bleached and deodorized palm olein and banana chips after deep‐fat frying

The changes in quality characteristics of refined, bleached and deodorized (RBD) palm olein used for deep‐fat frying of banana chips (180°C for 3 min at 17 min intervals for 2 h day^?1, to give six fryings per day and 30 fryings over five consecutive days) were studied. Four frying systems were used: RBD palm olein without antioxidant (system 1); RBD palm olein with 0.2 g kg^?1 α‐tocopherol (system 2); RBD palm olein with 1 g kg^?1 oleoresin rosemary (system 3); and RBD palm olein with the combination of 0.1 g kg^?1 α‐tocopherol + 0.5 g kg^?1 oleoresin rosemary (system 4). Fried oil samples were analysed for fatty acid composition, peroxide value (PV), anisidine value (AnV), totox value, free fatty acids (FFA) value, iodine value, at 232 and 268 nm, colour and viscosity. The crispness and sensory evaluation of the banana chips fried in this study were also evaluated. The results showed that RBD palm olein with added antioxidant reduced PV, AnV, totox value, at 232 and 268 nm, FFA and viscosity. The order of effectiveness in inhibiting oil oxidation in RBD palm olein was: oleoresin rosemary > α tocopherol + oleoresin rosemary > α‐tocopherol > control. For the crispness, the force values of banana chips fried in all systems were comparable. Sensory evaluation of fried banana chips for each system showed that there was no significant (P > 0.05) difference in terms of colour, flavour, odour, texture and overall acceptability. Copyright © 2003 Society of Chemical Industry     

Reduction of Oil Absorption in Deep‐Fried,Battered, and Breaded Chicken Patties Using Whey Protein Isolate as a Postbreading Dip: Effect on Lipid and Moisture Content

ABSTRACT: The effectiveness of whey protein isolate (WPI) solution as a postbreading dip to reduce oil absorption in deep‐fried, battered, and breaded chicken patties was investigated. Chicken patties were battered, breaded with either crackermeal or Japanese breadcrumbs, and dipped in WPI solutions prepared at 4 different protein concentrations (0%, 2.5%, 5%, and 10%, w/w WPI) that were adjusted to pHs 2, 3, and 8 before being deep fried. Undipped chicken patties served as the control. Overall, the most effective treatment was observed for WPI solutions made at high concentrations (5% and 10% WPI) at low pH levels (pHs 2 and 3). The highest lipid reduction observed for crackermeal patties (CMP) was 31.2% for patties treated with 5% protein solutions at pH 2 while the highest lipid reduction for Japanese breadcrumb patties (JBP) was 37.5% for patties treated with 10% protein solutions at pH 2. Oil degradation and batter, breading, and whey pickup did not significantly affect final lipid and moisture content. Moisture content was generally lower in patties treated at low pH levels (pHs 2 and 3). The results indicate that the usage of WPI as a postbreading dip is a promising alternative in reducing fat content in fried foods since it could simultaneously fulfill the steady demand for fried foods and contribute to the growing effort of Americans to consume less fat.     

Production of lipase‐catalyzed solid fat from mustard oil and palm stearin with linoleic acid by response surface methodology

BACKGROUND: Solid fat was produced from mustard oil and palm stearin through lipase‐catalyzed reaction, in which linoleic acid was intentionally incorporated. For optimizing the reaction condition of melting point and ω6/ω3 fatty acids, response surface methodology (RSM) was employed with three reaction variables such as substrate mole ratio of mustard oil (MO) to palm stearin (PS) (X₁), reaction temperature (X₂) and reaction time (X₃). RESULTS: The predictive model for melting point of solid fat was adequate and reproducible due to no significant lack of fit (P = 0.0764), P‐value (0.0037) of the model, and satisfactory level of coefficient of determination (R² = 0.92). For the ω6/ω3 ratio model, R² and P‐value were 0.89 and 0.0132, respectively, but lack of fit was significant (P = 0.0389). The melting point of the produced solid fat was affected by substrate mole ratio, whereas reaction temperature and time had no significant effect. The ω6/ω3 ratio of solid fat was influenced by substrate mole ratio and reaction temperature but not by reaction time. Based on ridge analysis, lower ω6/ω3 ratio was predicted by decreasing substrate mole ratio and reaction time, and by increasing reaction temperature. CONCLUSIONS: For producing solid fat with a specific melting point of 34.57 °C, a combination of 1:2 (X₁), 65.17 °C (X₂) and 21.46 h (X₃) was optimized, and the optimization was confirmed under the same reaction conditions. The solid fat contained palmitic (37.8%), linoleic (24.8%), oleic (21.3%), and erucic acid (9.7%), and its solid fat content was 30.3% and 10.3% at 20 and 30 °C, respectively. Copyright © 2009 Society of Chemical Industry