酱制时间对传统酱卤猪肉制品风味及质构变化规律的影响

以猪肉为原料,对传统酱制过程中样品的挥发性风味物质、游离氨基酸及质构的变化进行研究。电子鼻主成分分析(PCA)发现酱制过程中样品风味变化明显,利用气相色谱—质谱联用(GC-MS)进一步分析样品的挥发性成分发现,样品中与香辛料相关的风味物质(邻伞花烃、萜烯类等)多数在酱制后期(60～120min)检出并积累,与脂肪氧化、氨基酸降解及美拉德反应相关的风味物质(己醛等)多数在酱制前期(0～60min)检出,且在较短时间内迅速积累。样品中总游离氨基酸的含量变化明显,原料肉中总游离氨基酸含量为289.45mg/100g,酱制过程中总体呈增加趋势,酱制120 min后达到最大值为415.60mg/100g。酱制过程中样品硬度及咀嚼性呈先上升后下降的趋势,结合感官评定发现酱制40～60min时样品的质构(硬度3 000～3 500g,咀嚼性1 300～1 600g)较好。酱制时间越长,样品的风味越好,但不利于样品质构的形成。整体感官评定表明,该酱制条件下酱制100min时样品品质最好。     

Modelling the influence of inulin as a fat substitute in comminuted meat products on their physico-chemical characteristics and eating quality using a mixture design approach

The effects of fat substitution using two commercial inulin products on the physico-chemical properties and eating quality of a comminuted meat product (breakfast sausage) were modelled using a specialised response surface experiment specially developed for mixtures. 17 treatments were assigned representing a different substitution level for fat with inulin. Sausages were formulated to contain pork shoulder, back fat/inulin, water, rusk and seasoning (44.3, 18.7, 27.5, 7 and 2.5% w/w). Composition, sensory, instrumental texture and colour characteristics were assessed. Fructan analysis showed that inulin was unaffected by heat or processing treatments. Models showed increasing inulin inclusions decreased cook loss (p < 0.0017) and improved emulsion stability (p < 0.0001) but also resulted in greater textural and eating quality modification of sausages. Hardness values increased (p < 0.0001) with increasing inulin concentration, with panellists also scoring products containing inulin as less tender (p < 0.0112). Optimisation predicted two acceptable sausage formulations with significantly lower fat levels than the control, which would contain sufficient inulin to deliver a prebiotic health effect.     

Variability in temperature distribution and cooking properties of ground pork patties containing different fat level and with/without salt cooked by microwave energy

This study was carried out to evaluate the cooking effects of fat level (10% and 20%) with and without NaCl (1.5%) on the microwave cooking pattern and properties of ground pork patties. Each patty was cooked from a thawed state to 76.7°C in a microwave oven with full power (900W). Cooking rate in patties produced without salt was not affected by fat level, but the addition of salt in pork patties decreased cooking rate, regardless of fat levels. The temperatures at the edges of the patties increased faster than those at the center or the mid-way positions. In the patties with NaCl, the temperature of the center position was higher than that of the mid-way position. Patties containing salt within the same fat level had higher moisture content and lower fat content than those without salt, although no significant differences in compositional properties were observed between the center, midway, or edge positions. Total cooking loss, drip loss, and reduction in diameter and thickness were higher in patties with 20% fat compared to those with 10% fat, but the addition of salt resulted in reduction, regardless of fat level. Also, the addition of salt increased the redness and reduced yellowness of the cooked products.     

Effect of heating temperature,pH, concentration and starch/whey protein ratio on the viscoelastic properties of corn starch/whey protein mixed gels

The viscoelastic properties of corn starch (CS) gels were more dependent on heating temperature, while the properties of whey protein isolate (WPI) gels were more dependent on pH. Thus heating temperature (75, 85, 95 °C) and pH (5, 7, 9) were varied to obtain a series of mixed gels with interesting viscoelastic properties. WPI gels showed extensive stress relaxation (SR) indicative of a highly transient network structure, while CS gels relaxed very little in 2000 s. Based on SR results, it appeared that CS/WPI mixed gels with 25 and 50% CS formed compatible network structures at 15% total solids only at pH 9. This supposition was supported by SEM microstructures obtained for dehydrated gels and a synergistic increase in the large‐strain fracture stress for these gels. Some synergy was also found for mixed gels at 30% total solids at pH 9, while at pH 7 the mixed gels seemed to contain separate additive WPI and CS networks unlike the case for pH 7 at 15% total solids. In both cases (15 and 30% total solids) the degree of elasticity of the mixed gels decreased as the WPI content increased. Mixed gels (CS:WPI = 0.5) at pH 9 showed increased fracture stress and fracture strain relative to the same gels at pH 7. This suggests that a unique chemical compatibility exists at pH 9 and results in gels that combine the elasticity of CS and the internal stress dissipation of WPI. © 2001 Society of Chemical Industry     

Effect of pasteurization and fat,protein, casein to serum protein ratio,and milk temperature on milk beverage color and viscosity

Our goal was to determine the effect of pasteurization-homogenization, fat and protein concentration, proportion of milk protein that is casein and serum protein, and temperature on sensory and instrumental measures of viscosity and color of milk-based beverages. A second goal was to use instrumental measures of whiteness and yellowness to predict sensory measures of whiteness and yellowness. A complete balanced 3 factor (fat, true protein, and casein as a percentage of true protein) design was applied with 3 levels of fat (0.2, 1.0 and 2.0%), 4 levels of true protein (3.00, 3.67, 4.34, and 5.00%) within each fat level, and 5 levels of casein as a percentage of true protein (CN%TP; 5, 25, 50, 75, and 80%) within each protein level for beverage formulation. Instrumental color and viscosity, and visual sensory color analyses were done on each beverage formulation. For unpasteurized beverages across 3 fat levels (0.2, 1, and 2%), changes in CN%TP had the largest effect on L values, sensory whiteness, opacity, color intensity, and yellowness, whereas changes in fat concentration had a stronger influence on a and b* values. Increasing CN%TP from 5 to 80% increased L values, sensory whiteness, and opacity, and decreased sensory color intensity and yellowness. The a and b* values increased with increasing fat concentration. For unpasteurized milk protein beverages within each fat level, variation in CN%TP dominated the changes in L values, sensory whiteness, and opacity, and decreased a and b* values, sensory color intensity, and yellowness. The effect of heat (pasteurization and homogenization) and its interaction terms had the second largest effect on color of milk protein beverages with respect to instrumental color data and sensory appearance attributes. Heat increased L values, sensory whiteness, and opacity, and decreased a and b* values, sensory color intensity, and yellowness. Increases in temperature decreased instrumental viscosity and changes in protein concentration and CN%TP had a greater effect on instrument viscosity data within each temperature (4, 20, and 50°C) than fat. Sensory perception of yellowness was not highly correlated with b* values. Multiple linear regressions of L, a, and b* values produced more robust predictions for both sensory whiteness and yellowness than simple linear regression with L and b* values alone, and may be a useful instrumental approach for quality control of sensory whiteness and yellowness of milk protein beverages.     

Effect of the cooking on physicochemical and starch digestibility properties of two varieties of common bean (Phaseolus vulgaris L.) grown under different water regimes

Growing and cooking conditions influence the quality and nutritional value of beans. The objective of this research was to determine the effect of cooking on digestibility and physicochemical properties of two varieties of bean grown under different water regimes. Black 8025 and Pinto Durango varieties were grown in irrigated and temporal (rain fed) conditions in two locations of Guanajuato, Mexico. The pasting profiles of the cooked beans showed a significant decrease in viscosity. The enthalpy of the raw and cooked beans ranged from 2.75 to 3.95 and 0.62 to 0.97 J/g, respectively. The percentage of rapidly digestible starch and slowly digestible starch increased, while the percentage of resistant starch was lower in cooked samples. Black 8025 beans had lower glycemic index than Pinto Durango, but no significant difference (P < 0.05) was noted between water regimes. The variety of bean had a more pronounced effect on digestibility properties than the water regime.     

Effect of heating temperature and duration on the texture and protein composition of Bighead Carp (Aristichthys nobilis) muscle

The effect of heating temperature and duration on the texture and protein composition of bighead carp (Aristichthys nobilis) muscle was investigated. Samples were heated at 90°C, 100°C, 110°C, and 120°C for different times. The results showed that cooking loss increased significantly with increasing temperature and heating time, and a fractional conversion model was used to describe the increase. Hardness, chewiness, and gumminess exhibited a similar four-phase change with two peaks at 90°C, 100°C, and 110°C, and the trend was not observed at 120°C. Analysis of sodium dodecyl sulfate polyacrylamide gel electropheresis (SDS-PAGE) revealed that contents of myosin heavy chain decreased entirely to disappear and contents of actin significantly decreased. Increasing the intensity of the heavy molecular weight bands indicated the aggregation of myosin. Content of water-soluble proteins presented an increasing trend, which reflected the protein degradation and the release of low-molecular-weight compounds.     

Effect of high pressure, temperature, and storage on the color of porcine longissimus dorsi

The color of pork longissimus dorsi high pressure (HP) treated at 200 to 800MPa at 5 and 20°C for 10min was determined to a high degree by pressure level and to a lesser degree by temperature. Severe color changes appeared up to a threshold pressure at 400MPa. HP treatment at 20°C compared to 5°C resulted in meat, which was less red and slightly lighter. Storage at 2°C for 6days had no effect on lightness due to no further protein denaturation, but meat HP treated above 300MPa became significantly less red and more yellow within the first day of storage. Reflectance spectra showed that a short-lived ferrohemochrome myoglobin species was formed during HP treatment at 300 to 800, but transformed into a brown, ferric form of the pigment within the first day of storage. This explains the observed changes in the redness and yellowness after one day of storage.     

Effects of light,temperature and water activity on the kinetics of lipoxidation in almond-based products

Lipoxidation in almond-derived products was investigated using the chemiluminescence (CL) and thiobarbituric acid-reactive substances (TBARS) methods to detect the first and later reaction products, respectively. The effects of light during storage at 5 °C, 22 °C and 40 °C were studied, as well as the effects of combined heat/water activity treatments in the 60–120 °C and 0.38–0.72 range. During storage, light was found to enhance the CL and TBARS values, and specific responses were observed in almond paste and the final Calisson product. During the heating of almond paste, as the initial water activity (a_w) increased, the CL rate constants increased during heating to 60 °C and 80 °C, but interestingly, these values decreased during further heating to 120 °C, whereas the maximum TBARS rate constants occurred at a_w 0.57 at all the heating temperatures tested. The activation energies, based on the CL and TBARS values, decreased specifically when the a_w increased from 0.38 to 0.72, giving overall values ranging from110 kJ mol⁻¹ to 60 kJ mol⁻¹. Likewise, in the same water activity range, the temperature-dependent rate constant enhancing factor (Q₁₀) decreased from 3.3 to 1.6.     

Modelling the effect of temperature and lipid content on anchovy (Engraulis anchoita) salting kinetics

The effect of initial lipid content and temperature on the salting behaviour of anchovy (Engraulis anchoita) was studied. For this purpose brining of anchovy with variable initial lipid content (2.69–7.76 g 100 g⁻¹) was performed at temperatures between 5 and 35 °C. The obtained results indicate that initial mass transfer rate increased with brining temperature. Moreover, mass transfer rate was inversely related to the initial lipid content. In order to explain the dependence of the mass transfer rate on these variables two novel mathematical models were proposed. It was determined that both, salt gain and water loss rate constants depend on initial lipid content, whereas temperature only affects constants for salt transfer. In addition, salt gain constants depend linearly with initial lipid content and inversely with brining temperature. On the other hand, water loss rate constant was a function of the initial lipid content, fitting to a quadratic equation.     

Effects of temperature and NaCl percentage on lipid oxidation in pork muscle and exploration of the controlling method using response surface methodology (RSM)

This study investigated the effects of temperature (15, 20, 25, 30 or 35 °C) and sodium chloride (NaCl) (0.5%, 1.0%, 2.0%, 3.0% or 4.0%) on lipid oxidation by measuring the peroxide value (PV) and thiobarbituric acid reactive substances (TBARS) in minced pork muscle. Both temperature and NaCl showed significant (P < 0.05) pro-oxidant effect within studied range. The activation energy (92.35 kJ/mol) for PV was higher than that (65.66 kJ/mol) for TBARS, indicating that lipid primary oxidation was more affected by temperature than the secondary oxidation. Temperature and NaCl had extremely significant (P < 0.001) interaction for lipid oxidation. Elevating temperature could significantly (P < 0.05) decrease the threshold value of NaCl concentration affecting lipid oxidation in the minced pork muscle. Based on the results, a relatively high temperature and a moderate or slightly lower level of NaCl, are recommended conditions for the fastest lipid primary oxidation rate in pork muscle.     

Effect of carbon monoxide in modified atmosphere packaging, storage time and endpoint cooking temperature on the internal color of enhanced pork

The objective of this research was to evaluate the effects of gas atmosphere, refrigerated storage time, and endpoint temperature on internal cooked color of injection-enhanced pork chops. Enhanced chops were packaged in 0.36% CO/20.34% CO₂ (CO-MAP), 80% O₂/20% CO₂ (HO-MAP), or PVC-overwrapped (PVC-OW; controls), stored at 4 °C for 0, 12, 19 or 26 days, displayed for 2 days then cooked to six endpoint temperatures (54, 60, 63, 71, 77, and 82 °C). L^*, a^*, and b^* values, hue angle and chroma were determined on the internal cut surface of cooked chops. Chops packaged in CO-MAP had the highest a^* values; a^* value began increasing on day 14. The lowest hue angles occurred in chops cooked to lower endpoint temperatures. Chops in CO-MAP had lower hue angles and higher chroma than those in HO-MAP and PVC-OW. Above 71 °C, hue angle and chroma increased. Overall, CO-MAP packaged chops stored for longer time periods then cooked to lower endpoint temperatures appeared reddest. HO-MAP packaged chops were less red, did not change over time, and appeared more well done at lower endpoint temperatures than those in other gas atmospheres. CO-MAP packaged chops retained redness even after cooking at 82 °C.     

Effect of milk protein standardisation using buffalo milk protein co-precipitates on the texture,composition and yield of paneer

Buffalo milk was utilised for preparing paneer samples after standardisation of protein:fat ratio to 0.68 with the addition of buffalo milk protein co-precipitates (BMPC). These paneer samples along with control paneer (from buffalo milk) were analysed for yield, composition, microstructure, sensory, texture profile and protein loss in whey during manufacture. Paneer prepared using BMPC was considerably higher in yield and recovery of total solids, protein and calcium content than control paneer and could withstand the frying conditions in terms of retention of shape and integrity. Texture profile analysis and microstructure evaluation revealed the differences in textural properties of paneer samples prepared using BMPC with control paneer.     

Modelling the effect of temperature and water activity on the growth of Aspergillus parasiticus on irradiated Argentinian flint maize

A full factorially designed experiment including storage temperature (10, 20, 30 and 37 °C) and water activity (0.88, 0.92 and 0.96) was undertaken to study the growth of Aspergillus parasiticus in maize samples. Kinetic parameters such as specific growth rate (μ), lag phase duration and maximum logarithmic increase were determined by fitting the Modified Gompertz equation to the viable mould count data (N in CFU/g) as a function of time collected in twelve experiments. The average coefficient of determination (R²) was 0.987, being the mean standard deviation of the estimate of 0.216 in units of log₁₀N. In the practical range of 10-30 °C, the relationship of the three kinetic parameters with temperature was described by second order polynomial expressions, whose parameters, in turn, depended on water activity. The combined or full model i.e., the Modified Gompertz model with its parameters expressed as a function of temperature and water activity, was able to predict log₁₀N with an average percentage error of 4.3, so agreement with the experimental data was highly satisfactory.In a simulation exercise, the full model was able to predict the viable mould count, given an initial value and grain temperature and water activity histories, with promising results for maize storage.     

Effect of a commercial freeze/tempering process on the viability of Cryptosporidium parvum oocysts on lean and fat beef trimmings

Lean and fat beef trimmings (25 cm⁻²) were inoculated with approximately 250,000 Cryptosporidium parvum oocysts, placed in commercial packages (28 kg boxes) and subjected to normal commercial processes i.e. blast frozen (to −20 °C within 60 h), stored (−20 °C, 21 days), tempered (48 h at −3 °C), and held at 0 °C for 10 h. Inoculated areas were then excised, pulsified (30 s in 50 ml PBST), and centrifuged (2500×g, 15 min). The resultant pellet was resuspended in 10 ml water and subjected to immunomagnetic separation and viability dye assay. Following the commercial freeze/tempering process the viability of the oocysts had decreased from 90.6% viable in the working stock suspension to 7.17% and 9.46% viable on lean and fat trimmings, respectively. The results of this study indicate that if C. parvum oocysts were present on beef trimmings their viability would be substantially reduced as a result of the freeze/tempering process.     

Effect of water content and temperature on glucosinolate degradation kinetics in broccoli (Brassica oleracea var. italica)

The effect of water content and temperature on glucosinolate thermal degradation in broccoli (Brassica oleracea var. italica) was investigated. Broccoli was freeze dried obtaining batches with water content between 13% and 82% (a_w from 0.32 to 0.99). These samples were heated at different temperatures (from 60 to 120 °C) and glucosinolate levels were monitored. To rule out enzymatic breakdown, myrosinase was inactivated prior to heating. Degradation could be described by first-order kinetics for all glucosinolates and all water contents. In the temperature range 60–100 °C the sample with 13% showed the lowest degradation rate, whereas at 120 °C the degradation rate increased with the water content. This particular behavior was reflected by the high activation energy value of the driest sample. Several hypotheses to explain the observed behavior are discussed.     

Modelling the effect of temperature and water activity on the growth rate and growth/no growth interface of Byssochlamys fulva and Byssochlamys nivea

The purpose of the present study was to apply a modelling approach to define the growth rate and growth/no growth interface of Byssochlamys fulva and Byssochlamys nivea on a synthetic medium as a function of temperature and water activity. Both fungal species were grown on malt extract agar at different temperatures (10, 15, 20, 25, 30, 35, 40 and 45 °C) and a_w levels (0.88, 0.90, 0.92, 0.94, 0.96 and 0.99) for a period of 30 days. Growth responses were evaluated over time in terms of colony diameter changes. Growth data were fitted to the primary model of Baranyi and the resulting growth rates were further modeled as a function of temperature and water activity using the cardinal model with inflection (CMI) ( Rosso et al., 1993). A logistic regression quadratic polynomial model was also employed to predict the probability of growth over storage time. Estimated parameters for minimum, maximum and optimum temperatures for growth were 9.1 °C, 46.4 °C and 32.1 °C for B. fulva and 10.5 °C, 43.2 °C and 32.1 °C for B. nivea. The respective values for a_w were 0.893, 0.993 and 0.985 for B. fulva and 0.892, 0.992 and 0.984 for B. nivea. No growth was observed at 0.88 a_w regardless of temperature for both species, whereas B. nivea ascospores could not grow at 10 and 45 °C irrespective of a_w. Regarding growth boundaries, the degree of agreement between predictions and observations was >98% concordant for both species. The erroneously predicted growth cases were 1.4–4.2% false positive and 2.1–3.5% false negative for B. nivea and B. fulva, respectively. The developed logistic model was validated with two literature data sets as well as with data from independent experiments carried out on fruit juices. Validation results showed that agreement with literature data for growth was 25 out of 36 (69.4%) cases, whereas validation on fruit juice data failed in only 6 cases (5 false positives and 1 false negative) out of 128 cases.     

Effect of heating temperature and sodium chloride concentration on ultrastructure and texture of gels made from giant squid (Dosidicus gigas) with addition of starch,l-carrageenan and egg white

This paper seeks to compare the ultrastructure of gels made from frozen muscle of giant squid (Dosidicus gigas) at various temperatures with a number of different rheological parameters, with reference to a variety of added ingredients (non-muscle proteins and hydrocolloids) and to NaCl concentration. Interesting data on gel rheological properties were found where formulae containedl-carrageenan, starch and egg white, with a low salt concentration (1.5%). This seems to be because carrageenan forms an independent network which supports the principal structure formed by the fish protein; starch is incorporated into the network and retains water; and egg white forms a supplementary network which helps to improve rheological properties.     

Effect of preliminary processing and method of preservation on the content of selected antioxidative compounds in kale (Brassica oleracea L. var. acephala) leaves

Vitamin C and polyphenol content as well as total antioxidative activity were investigated in fresh leaves of kale; in leaves after blanching or cooking; and in frozen and canned leaves. In 100 g fresh matter, kale leaves contained 384.9 mg polyphenols and 112.1 mg vitamin C, with a Trolox equivalent antioxidant capacity (TEAC) level of 1175 μM Trolox. Of the polyphenols identified in kale leaves, ferulic acid occurred in the highest amount (240.44 mg/100 g, constituting 62% of total polyphenols). Freezing was a better method of preserving kale leaves since the loss of nutritive constituents was lower than in the case of canning. Depending on preliminary processing and storage temperature, after one-year storage frozen leaves contained 82.9–171.3 mg polyphenols and 39.3–65.4 mg vitamin C, with TEAC at the level of 501–681 μM Trolox in 100 g. In canned leaves these values were: 91.3–94.1 mg polyphenols, 16.1–19.3 mg vitamin C and 268–293 μM Trolox.