COMPARATIVE STUDY OF CORN GERM AND SOY PROTEINS UTILIZATION IN COMMINUTED MEAT PRODUCTS1

Soy flour (SF), soy concentrate (SC) and corn germ protein flour (CGPF) at 3.5%, or 2% of soy isolate (SI) were incorporated in the formulations of frankfurters. There was no significant differences in proximate composition of frankfurters containing SF, SC. SI, and CGPF. Frankfurters formulated with high plant protein flour had lower cholesterol, and higher protein content than the all-meat control frankfurters. Control frankfurters had lower water holding capacity and higher cooking losses than those containing plant proteins. No significant differences (P < 0.05) were found in textural and color characteristics. Atypical aroma and flavor profiles increased in frankfurters with SF nd CGPF extension.     

Emulsifying Capacity and Emulsion Stability of Soy Proteins Compared with Corn Germ Protein Flour

Both emulsifying capacity (EC) and emulsion stability (ES) increased with increasing concentrations from 0.4% to 0.8% of soy flour (SF), soy concentrate (SC), soy isolate (SI) and corn germ protein flour (CGPF) when studied by response surface methodology. EC and ES increased as pH increased from 6 to 8 in all samples. Increasing incubation temperatures of protein solutions from 20–70°C or from 4–20°C did not affect EC or ES, respectively. SF had the highest EC, followd by SI, SC, and CGPF.     

Water Retention and Solubility of Soy Proteins and Corn Germ Proteins in a Model System

Response surface methodology was used to study water retention and protein solubility of soy flour (SF), concentrate (SC), and isolate (SI), and corn germ protein flour (CGPF). Water retention increased with pH (6 to 8) and incubation temperature (10–70°C), but not with increasing incubation time (10–30 min). SC had highest water retention per gTam, followed by CGPF, SF, and SI. Water retention in relation to protein content was higher in CGPF than in the three soy products. Protein solubility was significantly affected by pH and temperature of incubation. Protein solubility increased when pH (6 to 8) and incubation temperature increased (30–70°C) in all samples. SI had highest protein solubility, and CGPF had the lowest.     

FUNCTIONALITY OF MILK PROTEINS AND CORN GERM PROTEIN FLOUR IN COMMINUTED MEAT PRODUCTS1

Effects of corn germ protein flour (CGPF), nonfat dry milk (NFDM), whey protein concentrate (WPC), and sodium caseinate (SC) on quality characteristics of comminuted meat products were studied. Water holding capacity (WHC) was lowest and cooking loss was highest for the control formulation, whereas formulations extended with CGPF and milk proteins were higher in WHC and lower in cooking losses. Shear force and firmness increased as extenders were added, except WPC. All frankfurters with extenders were firmer than the control, except those extended with WPC. Hue angle was highest for samples with CGPF, while no differences were found in hue angle between control and milk proteins containing samples, except samples with WPC. Frankfurters with CGPF and SC add had a stronger atypical aroma than the control. Meaty aroma score was higher for the control than for the other products, except those with WPC. Meaty flavor score was higher for the control than for all other products. The product with CGPF added had a stronger atypical flavor than the control. Frankfurters containing extenders were not as juicy as the all-meat control.     

Fat, Soy and Carrageenan Effects on Sensory and Physical Characteristics of Ground Beef Patties

Sensory and physical characteristics of beef patties containing 20% fat, 8% fat, or 8% fat plus 20% soy protein isolate (SI), soy flour (SF), soy concentrate (SC), or a mixture (MIX) of carrageenan (0.5%), starch (0.5%), and phosphate (0.2%) were compared after 0, 4, 8, and 12 wks storage at - 18°C. MIX had higher Hunter a* values than other treatments. Cook loss was lowest for MIX and highest for all beef patties. Soy extenders decreased beefy flavor and increased off-flavor scores. Time in frozen storage increased off-flavor, rubbery texture, and TBA value, and decreased red color and Hunter b* value of ground beef patties. Quality may be lowered in frozen-stored high fat, or low-fat-soy extended beef patties.     

MEASURING CHARACTERISTICS OF FRANKFURTERS EXTENDED WITH SORGHUM FLOUR1

Inclusion of 2, 3.5 or 5% sorghum flour in frankfurters had no significant influence on pH, viscosity or thermal stability of batters. Water‐holding capacity was lower for batter containing 5% sorghum flour. The level of sorghum flour had no effect on proximate composition, mechanical, sensory or shelf‐life measurements. Leucine and isoleucine levels and saturation index decreased with the incorporation of 5% sorghum flour. Storage period at 6/pm 1C also had no effect on sensory measures of frankfurters. However, water activity and TBA values of frankfurters increased after 15 days of storage; no further increases were found after 30 days. Microbial colony forming units could be detected only after 30 days and did not increase further. Total volatile nitrogen did not increase until day 40 of storage. No interactions were found between level of sorghum flour and day of storage for any of the parameters tested. Up to 5% sorghum flour can be used in frankfurters without adverse effects.     

CORN GERM PROTEIN IN FRANKFURTERS: TEXTURAL,COLOR, AND SENSORY CHARACTERISTICS AND STORAGE STABILITY1

Textural properties, water holding capacity, color, sensory characteristics, and storage stability of frankfurters containing hexane-defatted corn germ protein (CGP) as a meat extender were studied. CGP was incorporated at 2 and 3% levels as a powder or a preswelled slurry. Batter viscosity and shear force values of frankfurters were increased by the preswelled CGP. The redness values of the experimental samples with 2 and 3% CGP added as a powder were less than those of controls. There were no significant effects of CGP incorporation or its preswelling on the initial sensory properties of frankfurters. Meaty flavor and aroma and off-flavor acceptability decreased during 45 days of storage. Off-flavor and off-aroma of frankfurters showed a slight increase with time in storage. Total volatile nitrogen and nonammonia amino nitrogen of experimental and control frankfurters were not significantly different.     

Quantification of volatile compounds in Chinese soy sauce aroma type liquor by stir bar sorptive extraction and gas chromatography-mass spectrometry

BACKGROUND: Considering the important of aroma compounds on the quality of baijiu, stir bar sorptive extraction (SBSE) coupled with gas chromatography–mass spectrometry was applied to the aromas analysis of baijiu (Chinese liquor). RESULTS: Based on the results of optimization, a total of 76 volatile compounds were identified from 14 Chinese liquors, including 25 esters, 10 alcohols, 9 aldehydes and ketones, 8 aromatic compounds, 5 furans, 3 nitrogen‐containing compounds, 6 acids, 4 phenols, 3 terpenes, 1 sulfide‐containing compound, 1 lactone, and 1 acetal. By principal component analysis based on quantification results, 14 Chinese liquor samples could be classified into three groups. CONCLUSION: SBSE is a fast, simple, effective, and reliable method for extracting volatile compounds from Chinese liquor. The chemometrics approach revealed that LJ liquor with soy sauce aroma could exhibit more prominent sauce flavor through extending the time of storage, and its peculiar manufacturing practice was responsible for the soy sauce flavor. Copyright © 2011 Society of Chemical Industry     

Aroma Characteristics of Corn Germ Protein Flours

Eight sensory attributes were established to differentiate aroma characteristics among four kinds of corn germ protein flours (CGPF) processed by treatments to improve flavor quality. The projections of sample and conceptual spaces on a two-dimensional scale reflected aroma differences among samples evaluated by panelists. Volatiles of samples were separated by gas chromatography, and peaks that elicited olfactory responses were recorded as instrumental data. The projections of sample and volatile compound spaces reflected changes of volatiles by treatments. Relationships between sensory and instrumental data were elucidated by superimposing the two spatial maps. In general, treated CGPF samples had less grainy, brown, corn-like and sweet notes than untreated CGPF samples. However, there were more green, musty and chemical notes in the treated CGPF samples.     

Soybean Flour Lipoxygenase lsozyme Mutant Effects on Bread Dough Volatiles

Lipoxygenases are implicated in improvement of bread quality after addition of enzyme active soy flour. However, differences among the three major isozymes in soybeans in terms of impact on bread characteristics are not known. Differences exist among soybean lipoxygenase isozymes in terms of stability and generation of volatile flavor and aroma. Soybean flour with different lipoxygenase isozymes present might affect bread dough volatiles or defatting may affect activity of the isozymes. Full fat or defatted soy flour could be added to bread dough. Defatting selectively reduced lipoxygenase 2 activity with little effect on lipoxygenases 1 and 3. Addition of full fat soy flour from mutant isolines indicated that as with soybean homogenates, lipoxygenase 2 is mostly responsible for undesirable aroma compounds. Much higher levels of volatile alcohols were found in soy flour amended bread dough than in soy flour homogenates alone.     

FUNCTIONAL PROPERTIES OF SORGHUM FLOUR AS AN EXTENDER IN GROUND BEEF PATTIES 1

Patties were formulated with 20% fat ground beef and sorghum flour (SF) at 2, 4, and 6% levels (10, 20, and 30% as rehydrated 1:4 with water). Beef patties containing SF had higher pH, greater yield, less total cooking loss, less shrinkage in diameter, and less increase in thickness than those without SF. Water activity of cooked patties was not affected by addition of SF. Fat and water retentions of beef patties increased as the level of SF increased. Hunterlab a values (redness) for raw patties decreased as the level of SF increased, but a values for cooked patties were not influenced by level of SF. Shear force and compression of cooked patties decreased as the level of SF increased. Meat aroma and flavor decreased, but sorghum aroma and flavor of cooked patties increased as the level of SF increased. Tenderness of cooked patties increased as the level of SF increased, but juiciness of cooked patties was not affected.     

Functionality of Wheat Germ Protein in Comminuted Meat Products as Compared with Corn Germ and Soy Proteins

Wheat germ protein flour (WGPF), corn germ protein flour (CGPF), and soy flour (SF) were used as additives at a level of 3.5% in comminuted meat products (CMP). Frankfurters with protein additives showed increased water-holding capacity and batter stability and decreased cooking loss. Improved viscosity and adhesiveness were observed with protein additives when the level of added water was constant. Protein additives also influenced textural and sensory properties of frankfurters. WGPF at a level of 3.5% was found similar to effects of SF and CGPF. WGPF is a potential nonmeat protein additive that can be utilized as an extender in CMP such as frankfurters and bologna.     

Lipid Oxidation and Sensory Analysis of Cooked Pork and Turkey Stored under Modified Atmospheres

Precooked pork and turkey were stored at 4°C for 18 hr and at - 20°C for 3 months in vacuum and in atmospheres of air, carbon dioxide, and nitrogen. For both short-term refrigerated storage and long-term frozen storage, vacuum-packaging of precooked turkey and pork resulted in more meaty and less warmed-over flavor and aroma than the other packaging treatments. Samples stored in carbon dioxide and nitrogen atmospheres were less “oxidized” as indicated by sensory scores and TBA values than those stored in air but were more “oxidized” than vacuum-packaged meat. Warmed-over and rancid flavor and aroma scores correlated highly and consistently with TBA values, but inconsistently with the less sensitive fluorescence method. Vacuum-packaged turkey was darker and redder than other samples after frozen storage.     

腌腊鱼传统日晒干制过程中品质变化与香气形成

以腌制后的草鱼为研究对象,基于菌落总数、挥发性盐基氮含量、酸价（acid value,AV）、过氧化值（peroxide value,POV）、硫代巴比妥酸（thiobarbituric acid,TBA）值、色差、质构、脂肪酸组成、挥发性风味物质等指标,研究了腌腊鱼传统日晒干制过程中品质变化与香气形成规律。结果显示,菌落总数和挥发性盐基氮含量均随着日晒时间的延长而升高,日晒4?d时两者均达最大值,分别为4.73（lg（CFU/g））和28.39?mg/100?g,说明产品安全性好。随着日晒时间的延长,AV和TBA值不断增加,而POV呈先上升后下降趋势。色差和质构结果表明,日晒过程中腌腊鱼色泽不断变暗,逐步发红和变黄,同时硬度和咀嚼性上升,形成成品特有的“干香”风味。日晒4?d后,腌腊鱼不同脂质成分中多不饱和脂肪酸（polyunsaturated fatty acids,PUFA）相对含量均明显下降,且下降趋势排序为：游离PUFA＞磷脂PUFA＞甘油三酯PUFA。本研究共从腌腊鱼样品中检出了七大类70?种挥发物,筛选确定了己醛等14?种气味活性物质。日晒结束后,腌腊鱼成品中挥发物气味活性值总和从156.67升高至252.88,表明日晒加工对传统腌腊鱼制品的香气形成十分关键。本研究结果可为传统腌腊鱼加工企业完善生产工艺提供理论参考。     

STORAGE STABILITY OF COMMERCIALLY PREPARED AND FROZEN POND-RAISED CHANNEL CATFISH (Ictalurus punctauts, rafinisque)

SUMMARY –The storage stability of frozen pond-raised channel catfish from five commercial processing plants was examined. Three distinct types of processing treatment were included in the five lots. Fish samples were evaluated initially and at regular intervals during frozen storage up to 270 days. The evaluations included changes in moisture, pH, fat stability (TBA value) and shear press values of the uncooked fish, and in sensory ratings for appearance, aroma, color, texture and flavor of the cooked products. Moisture losses and changes in pH during frozen storage were not statistically significant (P = 0.05). Thiobarbituric acid (TBA) values indicative of changes in fat stability, incresed in all five lots of fish with prolonged storage but were not closely correlated with changes in flavor rating. Sensory ratings for quality of the cooked product decreased significantly with successive storage periods. The regression patterns representing changes in quality during storage varied among the different losts of fish. Certain variations were related to the processing treatments.     

Corn Germ Protein Flour as an Extender in Broiled Beef Patties

Beef patties were extended at levels of 10, 20, and 30% of the uncooked weight with hydrated defatted corn germ protein flour (CGPF). Extended patties had lower cooking losses and higher cooked yields than control patties. Adding CGPF did not affect moisture or fat contents in broiled patties, but lowered protein content. The amino acid composition of experimental patties was comparable to that of the control. The water-holding capacity and pH of raw patties increased with increasing levels of added CGPF. Incorporation of CGPF affected sensory characteristics of the product; meaty aroma and flavor of all-meat patties was significantly higher than experimental samples and decreased with an increase in added CGPF. CGPF has potential use as an extender in coarsely ground meats.     

老抽酱油储存期间关键气味物质分析及其风味特征的变化

为阐明老抽酱油在不同储存期的关键气味化合物及其风味特征的变化,采用液液萃取与气相色谱-嗅闻-质谱(GC-O-MS)相结合提取并鉴定不同储存期老抽酱油中的挥发性气味化合物,并利用香味提取物稀释分析(AEDA)鉴定关键气味化合物。结果表明:在老抽酱油样品中共检测到56种气味活性物质,其中FD因子>1024的化合物分别为2-甲基吡嗪、2,6-二甲基吡嗪、5-甲基-2(3H)-呋喃酮、2-乙酰基呋喃、2-乙酰基-5-甲基呋喃、1,4-丁内酯、5-甲基-2-呋喃甲醇、2-羟基-3-甲基-2-环戊烯酮、愈创木酚、麦芽酚和4-羟基-2,5-二甲基-3(2H)-呋喃酮 (HDMF),其中,2,6-二甲基吡嗪、5-甲基-2(3H)-呋喃酮、2-羟基-3-甲基-2-环戊烯酮、麦芽酚和HDMF的香气活性值>1,对老抽酱油整体香气起主要贡献作用。感官评价结果表明,老抽酱油随着储存时间的延长,烤香味和烟熏味的气味强度得分升高。该研究分析了老抽酱油的关键气味化合物以及在储存过程中气味特征变化,为老抽酱油相关风味研究提供了理论参考。     

Wheat Germ Protein Flour Solubility and Water Retention

The effects of pH and temperature on water retention (WR), protein solubility (PS), and total solubility (TS) of defatted wheat germ protein flour (WGPF) were studied in a model system. PS of WGPF was compared with those of corn germ protein flour (CGPF), soy flour (SF), nonfat dried milk (NFDM), and egg white powder (EWP) at 1–8%. WR increased with increase in pH from 4 to 8. Maximum WR occurred at 70°C, and slight variations were observed between 5 and 30°C. PS and TS increased with increases in pH and temperature. PS of proteins was in the order of NFDM > EWP > SF > CGPF=WGPF. The results showed the potential for usage of WGPF in comminuted meats, beef patties, breads, cakes, and cookies.     

Protein Solubility, Water Retention, and Fat Binding of Corn Germ Protein Flour Compared with Milk Proteins

Protein solubility (PS), water retention (WR), and fat binding (FB) of corn germ protein flour (CGPF), nonfat dry milk (NFDM), whey protein concentrate (WPC), and sodium caseinate (SC) were comparatively studied using response surface methodology. PS and WR of all samples were affected by pH except for WR of CGPF. PS and WR of all samples were not affected by incubation temperature except of WR of CGPF. Incubation temperature influenced FB of CGPF and WPC but not of NFDM and SC. Sample concentration significantly affected FB of all samples. CGPF was an effective protein source in terms of WR and FB. For FB, SC > CGPF = NFDM > WPC and for PS, WPC=NFDM=SC > CGPF.