Frying — Effect of coating on crust microstructure, color, and texture of lean meat portions

Trained sensory descriptors and volatile aroma compounds of USDA Select steaks using five grill temperatures

Thirty-three USDA Select boneless top loins were selected from carcasses at a commercial major packing plant, vacuum-packaged, and aged for 14 d (4 °C). The loins were then divided into 10 portions (5 grill temperatures for each of trained sensory panel and Warner-Bratzler shear force). Flat-top electric grills were pre-heated to 1 of 5 different temperatures: 149 °C (149), 177 °C (177), 204 °C (204), 232 °C (232), or 260 °C (260). Steaks were placed on the grill, turned when the internal temperature reached 35 °C and removed when the internal temperature reached 71 °C. A trained sensory panel evaluated ten basic flavors and five texture attributes. Extra cubes from each sample were frozen in liquid nitrogen and stored at -80 °C for GC/MS volatile aroma compound analysis. Beef identity, brown, and roasted flavor descriptors increased linearly (P < 0.001) while bloody/serumy tended to decrease (P = 0.016) and sour flavor decreased (P = 0.006) linearly as grill temperature increased. Furthermore, burnt (deviation P = 0.008) and bitter (deviation P = 0.012) flavor descriptors were affected by effects other than linear or quadratic, while umami (P = 0.002) and overall sweet (P = 0.016) flavors increased quadratically from 149 to 232 then declined at 260 grill temperatures. Two alcohols, eight aldehydes, four alkanes, three furans, eight ketones, and twelve pyrazines were impacted by differences the grill temperature. Increasing grill temperature increases volatile compounds, primarily from the Maillard reaction, that improve positive beef flavor descriptors.

Effects of Air Frying on French Fries: The Indication Role of Physicochemical Properties on the Formation of Maillard Hazards, and the Changes of Starch Digestibility

This study focused on the formation of Maillard hazards in air fried fries, highlighting the correlation between the resultant physical properties of the fries and the formation of Maillard hazards. In the meantime, the effects of air frying on the in vitro starch digestibility of fries were explored. Potato strips were fried at various temperatures (180-200°C) and time (12-24 min). Results indicated that the extent of browning, hardness, and the contents of Maillard hazards (acrylamide, 5-hydroxymethylfurfural, methylglyoxal, and glyoxal) all increased steadily with air frying temperature and time. Moisture content were negatively correlated (p < 0.001) with Maillard hazards content and physicochemical properties except for L^* with the correlation coefficients range from -0.53 to 0.94, and positively correlated with L^* value with correlation coefficient was 0.91, hence, reducing the Maillard hazard exposure while maintaining the desired product quality can be achieved by controlling the moisture content of the air fried French fries. Compared with deep frying (180°C-6 min), air frying decreased acrylamide and 5-hydroxymethylfurfural content with the maximum reduction rate were 47.31 and 57.04%, respectively. In addition, the in vitro digestion results suggested that air frying resulted in higher levels of slowly digestible starch (48.54-58.42%) and lower levels of resistant starch (20.08-29.34%) as compared to those from deep frying (45.59 ± 4.89 and 35.22 ± 0.65%, respectively), which might contribute to more balanced blood sugar levels after consumption. Based on the above results, it was concluded that air frying can reduce the formation of food hazards and was relatively healthier.

Effects of Konjac Glucomannan on Oil Absorption and Safety Hazard Factor Formation of Fried Battered Fish Nuggets

The purpose of this study was to investigate the effects of konjac glucomannan (KGM) on oil absorption and the formation of safety hazard factors in fried battered fish nuggets by measuring advanced glycation end products (AGEs) and acrylamide contents. Other physicochemical properties were determined to explore the reason for oil absorption and formation of safety hazard factors. The acrylamide was found mainly in the crust. The addition of 0.8% KGM could significantly reduce the acrylamide content (p < 0.05). For the battered sample, the AGEs content was far lower than the unbattered. The addition of 0.8% KGM could significantly reduce the AGEs content in the inner layer (p < 0.05). The microstructure showed that the sample with 0.8% KGM had the most compact crust. The compact crust reduced oil and malondialdehyde contents. Combined with the other indicators, the inhibitory effect of 0.8% KGM on acrylamide was closely related with the decreased extent of oil oxidation and Maillard reaction in the samples with 0.8% KGM. The inhibitory effect of 0.8% KGM on AGEs might originate from its lower oil content.

Quality Characteristics and Moisture Mobility of Giant Salamander (Andrias davidianus) Jerky during Roasting Process

Quality attributes and water mobility of giant salamander jerkies (GSJs) during roasting process (160°C, for 0, 20, 40, 60, and 80 min) were investigated. The results showed that $a^{\ast },b^{\ast }$ values and shear force increased of GSJs roasting from 20 to 80 min, while $L^{\ast }$ , yield, and moisture content decreased significantly ( $p<0.05$ ). Sensory assessment showed that GSJs at a roasting time of 40–60 min had higher scores. GSJs contained great amount of healthy unsaturated fatty acids (including DHA and EPA), and the total amino acids and essential amino acids were among 59.33–71.77 g·100 g−1 and 25.94–31.40 g·100 g−1, respectively. The mobility of the immobilized moisture and free moisture were shrunk dramatically during roasting. The proton density weighted images also exhibited the moisture shrinkage during roasting. In addition, T22 and T23 were positively correlated with MRI signal, moisture content, and yield of GSJs, but negatively correlated with shear force and overall acceptability, respectively. Thus, in view of various quality attributes and sensory evaluation, a roasting time of 40–60 min was favored for nutritive GSJs production. LF-NMR and MRI might be employed to profile the quality characteristics during roasting as a rapid and nondestructive analytical tool.

Selection of Vegetable Oils and Frying Cycles Influencing Acrylamide Formation in the Intermittently Fried Beef Nuggets

This study aims to investigate the effect of different vegetable oils and frying cycles on acrylamide formation during the intermittent frying of beef nuggets. Different vegetable oils, palm olein (PO), red palm olein (RPO), sunflower oil (SFO), and soybean oil (SBO), were used for a total of 80 frying cycles. Oil was collected at every 16th frying cycle and analyzed for peroxide value (PV), p-anisidine value (p-AV), free fatty acid (FFA), total polar compound (TPC), polar compound fractions, and fatty acid composition (FAC). Total oxidation (TOTOX) value was calculated, and acrylamide content was quantified in the nuggets. Regardless of the oil type, PV, p-AV, and TOTOX initially increased but gradually decreased. However, FFA and TPC continued to develop across the 80 frying cycles. The C18:2/C16:0 remained almost unchanged in PO and RPO but dropped progressively in SFO and SBO. The lowest acrylamide content in fried products was observed in the PO, while the highest content was observed in RPO. Bivariate correlation analysis showed no significant (p ≤ 0.05) correlation between oil quality attributes and acrylamide concentration. The oil type but not the frying cycle significantly affected the acrylamide concentration in beef nuggets.

Effect of Frying Conditions on Self-Heating Fried Spanish Mackerel Quality Attributes and Flavor Characteristics

In this study, we investigated the effects of different frying conditions on the quality characteristics of fried Spanish mackerel (Scaberulous niphonius) to address the food quality degradation of self-heating fish products after frying, sterilization, and reheating. Furthermore, the effect of different moisture contents (65%, 60%, 55%, and 50%) of fried Spanish mackerel on texture, color, and microstructure after sterilization and self-heating were examined. The flavor fingerprints of different frying temperatures (140 °C, 160 °C, 180 °C, and 200 °C) coupled with the optimal moisture content were identified; furthermore, volatile organic compounds (VOCs) were studied using headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS) with principal component analysis (PCA). The results indicated that the shear force value significantly increased, while the hardness and chewiness significantly decreased simultaneously with decreasing moisture content. Samples containing 65% moisture content showed the highest L*, a*, and W values, while their b* value was the lowest, and the most clearly visible fibrous veins with tiny cracks could be observed in them. Samples fried at 160 °C and 65% moisture content exhibited the richest VOCs, with a greasy or fried aroma. Based on the PCA, there were significant differences in the sample VOCs under different frying conditions. In summary, among all treatments, frying at 160 °C with 65% moisture content resulted in the highest food quality of fish filets. The results of this study could provide a theoretical basis for improving the food quality of self-heated fish products.

Comparison of quality and nutritional attributes of pond-cultured and container-cultured snakehead (Channa argus argus) fillets after being boiled, fried, and baked

The objective of this study was to compare the quality and nutritional attributes of snakehead (Channa argus argus) fillets (cultured in ponds and containers) after being heated (boiling, frying, and baking). The results revealed that there were few differences in quality (flavor, color, and texture) and nutritional attributes (content of amino acid, dipeptidyl peptidase IV (DPP-IV) and angiotensin I-converting enzyme (ACE) inhibition activity, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activity) of snakehead fillets obtained from two cultured modes. Container-cultured samples exhibited more beneficial effects on flavor (more esters) and bioactivity (ACE inhibition and DPPH scavenging activity) than pond-cultured. Frying increased flavor attributes but decreased nutritional value of fish. Boiling was an effective heating method for increasing quality and nutritional attributes of container-cultured snakehead fish. Generally, the container-cultured mode was applicable for culturing snakehead without decreasing quality and nutritional attributes, which deserved more attention. PRACTICAL APPLICATION: The study provided information about the differences of quality properties (flavor and texture) and nutritional attributes (bioactive functions of simulate-digested products) of pond-cultured and container-cultured snakehead fish after being heated. The results will provide some potential values for the application of container-cultured technology.

Effect of fermentation and postcooking procedure on quality parameters and volatile compounds of beef jerky

In this study, jerky samples were prepared from seasoned beef with and without the addition of starter culture. They were then dried or fried and analyzed to identify the quality parameters and volatile flavor compounds. Samples (starter and control) were divided into drying (inoculated-drying, I-D; noninoculated-drying, N-D) and frying (inoculated-frying, I-F; noninoculated-frying, N-F) groups. Water activity (a w), lightness (L*), and redness (a*) values were significantly affected (p < .001) by the postcooking procedures (drying or frying). Hardness, chewiness, and resilience were significantly lower in the dried groups than in the fried groups (p < .05). The formation of volatile compounds was affected by cooking treatment, with the highest levels observed in the I-F group. After frying, the most abundant flavor compounds in the I-D and N-D groups were terpenes and sulfur-containing compounds, followed by aromatic hydrocarbons, ketones, and alcohols. The most common compounds among all groups were acetoin, D-limonene, anethole, styrene, and tetramethylpyrazine. Overall, the jerky in the I-F group had the best color and tenderness scores among all groups.

Transport Mechanisms and Quality Changes During Frying of Chicken Nuggets--Hybrid Mixture Theory Based Modeling and Experimental Verification

Hybrid mixture theory (HMT) based 2-scale fluid transport relations of Takhar coupled with a multiphase heat transfer equation were solved to model water, oil and gas movement during frying of chicken nuggets. A chicken nugget was treated as a heterogeneous material consisting of meat core with wheat-based coating. The coupled heat and fluid transfer equations were solved using the finite element method. Numerical simulations resulted in data on spatial and temporal profiles for moisture, rate of evaporation, temperature, oil, pore pressure, pressure in various phases, and coefficient of elasticity. Results showed that most of the oil stayed in the outer 1.5 mm of the coating region. Temperature values greater than 100 °C were observed in the coating after 30 s of frying. Negative gage-pore pressure (p(w) < p(g)) magnitudes were observed in simulations, which is in agreement with experimental observations of Sandhu and others. It is hypothesized that high water-phase capillary pressure (p(c) > p(g)) in the hydrophilic matrix causes p(w) < p(g), which further results in negative pore pressure. The coefficient of elasticity was the highest at the surface (2.5 × 10(5) Pa) for coating and the interface of coating and core (6 × 10(5) Pa). Kinetics equation for color change obtained from experiments was coupled with the HMT based model to predict the color (L, a, and b) as a function of frying time.