We evaluated the effects of pre-cooking methods on the quality of reheated marinated pork loin. Frozen marinated pork loins cooked using various methods (boiling, grilling, pan frying, infrared cooking, and superheated steam cooking) were reheated in a microwave, and their pH, color, cooking loss, re-heating loss, total loss, thiobarbituric acid reactive substance (TBARS) value, sensory properties, and shear force were determined. Although all parameters varied with different cooking methods, lightness values and TBARS values showed the tendency to decrease and increase, respectively, after reheating. Superheated steam-cooked samples showed the lowest values of cooking loss, total loss, TBARS value, and shear force (p<0.05) and the highest lightness, redness, and yellowssness values and juiciness, chewiness, and overall acceptability scores (p<0.05). These results show that pre-cooking with superheated steam maintains the quality characteristics of marinated pork loin upon reheating. Therefore, pre-cooking with superheated steam may be beneficial for the commercial distribution of frozen cooked marinated pork loin.
Meat products prepared by microwave reheating are available in various forms in retail markets (Choi, 2009). Microwave cooking is non-uniform and characterized by edge overheating, absence of browning, and reduction in sensory scores (Risman, 1998). However, microwave is mostly used for reheating meals such as home meal replacer (HMR), as it provides advantages in terms of speed and convenience (Yarmand et al., 2013).
Pre-cooked meat products that are refrigerated and frozen before consumption develop an off-flavor called warmed-over flavor (Tims and Watts, 1958). Rapid lipid oxidation is considered as the primary contributor to warmed-over flavor, resulting in the decline in its acceptability (Choi, 2009). Some researchers have reported the effects of reheating methods on the quality characteristics of meat products (Lyon et al., 1988; Steiner et al., 1985). It is necessary to study preheating methods that may suppress warmed-over flavor of meat products. However, very few studies have focused on the definite reheating condition with various pre-cooked methods.
Here, we evaluated and compared the effects of different pre-cooking methods such as boiling, grilling, infrared cooking, pan cooking, and superheated steaming on marinated pork loin subjected to reheating up to an internal temperature of 75°C. In particular, the effect of each pre-cooking method on reheated marinated pork loin was evaluated with respect to pH, color, cooking loss, reheating loss, total loss, thiobarbituric acid reactive substance (TBARS) value, sensory evaluation, shear force, and correlation between quality characteristics of pork loin.
Pre-Cooking Pre-cooking means preparing your ingredients before cooking or food preparation stages that we can complete before customers make their orders. Pre-cooking includes preparing vegetables, sauces, curry ingredients, Yum ingredients, etc.
Cooking loss, reheating loss, and total loss
Cooking loss (%), reheating loss (%), and total loss (%) were determined by calculating the weight difference (g) between marinated pork loin before and after cooking as follows:Cooking loss (%)=Weight of raw pork loin−Weight of cooked pork loinWeight of raw pork loin×100Reheating loss (%)=Weight of reheated pork loin−Weight of cooked pork loinWeight of raw pork loin×100Total loss (%)=Cooking loss + Reheating loss
Lipid oxidation was analyzed in triplicates with some modifications in the TBARS method described by Tarladgis et al. (1960). The value was expressed as milligram of malondialdehyde (MD) per kilogram of sample. Briefly, 10 g samples were blended with 50 mL distilled water for 2 min using a homogenizer (AM-7, Nihon Seiki, Kaisha Ltd., Japan) and transferred to a distillation tube. The cup used for mixing was cleaned with 47.5 mL of distilled water, which was added to the same distillation flask along with 2.5 mL 4 N hydrochloric acid (HCl) and antifoaming agent (KMK-73, Shin-Etsu Silicone Co. Ltd., Korea). The mixture was distilled and 5 mL of 0.02 M thiobarbituric acid (TBA) in 90% acetic acid was added to the test tube containing 5 mL of the distillate and mixed. The tubes were closed and heated in boiling water for 30 min for chromogen development, followed by cooling at room temperature. The absorbance of the reaction mixture was measured at 538 nm against a blank using UV/VIS spectrophotometer (Kim et al., 2017).
Sensory evaluations were performed in triplicates on each sample by a panelist. A panel of 12 members including researchers from the Korean Food Research Institute (KFRI), Korea, was used to evaluate the marinated loin samples (Shim et al., 2018). Each marinated loin sample was evaluated in terms of appearance, color, flavor, juiciness, chewiness, and overall acceptability. Marinated pork loins were cooked with different methods until the core temperature reached 75°C. The samples were cooled to 20°C for 30 min, cut into quarters (width×length: 3×4 cm), and served randomly to the panelists. Each sample was coded with a randomly selected three-digit number. Sensory evaluations were performed under fluorescent lighting. Panelists were instructed to cleanse their palates with water between samples. The cooked samples were evaluated using a 9-point descriptive scale. This analysis was conducted using the hedonic test described by Bergara-Almeida and da Silva (2002).
Warner-Bratzler shear force was determined using the method of Choi et al. (2016) at room temperature with a texture analyzer (TA-XT2i, Stable Micro Systems Ltd., England). The cooked samples were cooled at 20°C for 30 min. Following equilibration, the samples were cut with a knife into 3×4 cm sections and the sections were sheared at separate locations with Warner-Bratzler blade set attached to a texture analyzer. The Warner-Bratzler shear force condition is head speed 2.0 mm/s, distance 8.0 mm, force 5.0 g, pre-test speed 2.0 mm/s, post-test speed 5.0 mm/s, and maximum load 50.0 kg.
All tests were performed at least thrice for each experimental condition and mean values reported. One-way analysis of variance (ANOVA) was performed on all variables using the general linear model (GLM) procedure of SAS (Statistical Analysis Systems Institute, 2008) statistical package. Duncan’s multiple range test (p<0.05) was used to determine the differences between treatment means. The statistical analysis for each parameter combined the data from three batches. Pearson’s correlation analysis was used to investigate the relationship between quality indicators and spot intensities (Choi et al., 2015). Correlation coefficients were calculated with CORR procedure of SAS.
Cooking and reheating marinated pork loin
Pork loin was purchased from a local processor 48 h postmortem. The curing solution comprised soy sauce (15%), sugar (6%), salt (1%), pepper powder (0.5%), onion powder (0.5%), garlic powder (0.5%), isolated soy protein (1%), and ice water (76%). The curing solution was added and the pork loin was tumbled using a tumbler (MKR-150C, Ruhle GmbH., Germany) at 0°C for 60 min under vacuum pressure (0.75 bar, 25 rpm). The tumbled pork loin samples were aged for 24 h, heat processed using the various cooking methods, and cooled at room temperature (24°C). The pre-cooking methods included boiling (water bath model 10-101, Dae Han Co., Korea), grilling (CG20, Hobart, USA), infrared cooking (ZG-BR377, Zaigle, Korea), pan frying (OES 6.06, Convotherm, Germany), and superheated steaming (DFC-240W, Naomoto, Japan). The pre-cooking treatment was stopped when the temperature at the center of meat samples reached 75°C, which is a generally recommended safe temperature for pork (Kim et al., 2013; Murphy et al., 2001). The treated meat samples were frozen (-15°C) after cooling to 20°C for 30 min. The frozen pork loin was reheated (after 5 days in frozen storage) using a microwave (NN-S963/S763, Panasonic Inc., Canada) at 720 W and 2,450 MHz. For reheating, each pork loin was placed in the center of the oven on a microwave-safe plastic container with a plastic rack until the targeted center temperature was 75°C. The cooked reheated marinated pork loins were cooled to a temperature of 4°C and packaged in polyethylene bag. This procedure was performed in triplicates for each marinated pork loin and all analyses were performed at least in triplicates for each batch.
The pH value of the sample was measured in a homogenate prepared with 5 g of sample and distilled water (20 mL) using a pH meter (Model 340, Mettler-Toledo GmbH, Switzerland). The pH meter was calibrated with standard 4.00, 7.02, and 10.05 pH buffers (VWR Scientific Products) at a temperature of 20±1°C.
The color of the flat surface in the center of each sample was determined using a colorimeter (Minolta Chroma meter CR-210, Minolta Ltd., Japan; illuminate C, calibrated with a white plate, L*=+97.83, a*=-0.43, and b*=+1.98). Lightness (CIE L*-value), redness (CIE a*-value), and yellowness (CIE b*-value) values were recorded.
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FAQ
What does pre-cooked food mean?
What is the meaning of precooking?
What is the meaning of pre prepared food?
What is a pre-cooking process?
Pre-cooking processes are processes which are responsible for turning raw materials into food ingredients. Processing methods in this category are often time-tested and mechanical in nature — with a few exceptions. Methods that remove harmful compounds from food ingredients often fall within this category.
What are pre-production processes?
Pre-production processes are processes which, while usually not regarded as part of “food processing”, can nevertheless affect the quality of food significantly. In some cases, these processes can even occur before the produces are harvested.
What is tertiary processing?
Tertiary processing: industrial-grade methods which turn food into refined food (e.g., artificial flavoring, fortification, fat hydrogenation) While food processing (and the related concept of processed food) can be perceived negatively, it is also sometimes a necessary step to ensure that the food we consume is safe and healthy. For example:
What is food processing?
Food processing is a very broad spectrum that ranges from basic technologies like freezing or milling, to the incorporation of additives that promote shelf stability or increase palatability. As a general rule, emphasizing unprocessed or minimally processed foods in the daily diet is optimal.