Nutritional comparison of fresh,frozen and canned fruits and vegetables. Part 1. Vitamins C and B and phenolic compounds

The first of a two‐part review of the recent and classical literature reveals that loss of nutrients in fresh products during storage and cooking may be more substantial than commonly perceived. Depending on the commodity, freezing and canning processes may preserve nutrient value. The initial thermal treatment of processed products can cause loss of water‐soluble and oxygen‐labile nutrients such as vitamin C and the B vitamins. However, these nutrients are relatively stable during subsequent canned storage owing to the lack of oxygen. Frozen products lose fewer nutrients initially because of the short heating time in blanching, but they lose more nutrients during storage owing to oxidation. Phenolic compounds are also water‐soluble and oxygen‐labile, but changes during processing, storage and cooking appear to be highly variable by commodity. Further studies would facilitate the understanding of the changes in these phytochemicals. Changes in moisture content during storage, cooking and processing can misrepresent changes in nutrient content. These findings indicate that exclusive recommendations of fresh produce ignore the nutrient benefits of canned and frozen products. Nutritional comparison would be facilitated if future research would express nutrient data on a dry weight basis to account for changes in moisture. Copyright © 2007 Society of Chemical Industry     

Fate of the fusarium mycotoxins, deoxynivalenol, nivalenol and zearalenone, during extrusion of wholemeal wheat grain

In the European Union, deoxynivalenol in cereals and cereal products is controlled by recent legislation with the objective of minimizing consumer exposure to this mycotoxin. Relatively few studies have examined the loss of Fusarium mycotoxins during processing and whether this is accurately reflected by the processing factors. The behaviour of deoxynivalenol, nivalenol and zearalenone during extrusion of naturally contaminated wholemeal wheat flour has been examined using pilot-scale equipment. Factors examined were temperature and moisture content. Concentrations of the three mycotoxins were little changed by extrusion although the amount of deoxynivalenol decreased at the lowest moisture content. However, this effect did not appear to be temperature-dependent, suggesting that the apparent loss is either due to binding or inability to extract the residue. Under some conditions, concentrations of the mycotoxins, particularly nivalenol, were higher after extrusion.     

FUNCTIONAL, MICROBIAL AND SENSORY CHANGES IN ICE-STORED SEA SCALLOPS (PLACOPECTEN MAGELLANICUS) TREATED WITH SODIUM TRIPOLYPHOSPHATE

Sea scallop adductor muscles were given six processing treatments involving water, phosphate and NaCl. They were evaluated during iced storage for changes in moisture content, aerobic plate count, pH, drip loss, cook loss, and sensory freshness attributes. All treated scallops and a wash control were above the 80% moisture interim federal compliance level. A dip in 10% sodium tripolyphosphate generally produced the least drip and cook losses and lowest aerobic plate counts during iced storage compared to freshwater washed scallops. No additional benefit was derived by very long exposure to solutions of sodium tripolyphosphate.     

Polysaccharides as Alternative Moisture Retention Agents for Shrimp

Phosphates are used as moisture retention agents (MRAs) by the shrimp industry. Although they are effective, phosphates are expensive, need to be listed on a food label, and overuse can often lead to a higher product cost for consumers. Polysaccharides were researched as alternative MRAs. Polysaccharides are usually inexpensive, are considered natural, and can have nutritional benefits. Research was conducted to determine whether polysaccharides yielded similar functional impacts as phosphates. Treatments included a 0.5% fibercolloid solution isolated from citrus peel, an 8% pectin solution, a 0.5% xanthan gum (XG) solution, a 1% carboxymethyl cellulose solution, and conventionally used 4% sodium tripolyphosphate (STP). Experimental treatments were compared to a distilled water control to gauge effectiveness. Freezing, boiling, and oven drying studies were performed to determine how moisture retention in shrimp differed using these different treatments. Water activity was measured to determine any potential differences in shelf life. Solution uptake was also determined to understand how well the treatments enhanced water binding. For moisture loss by freezing, 4% STP and the 0.5% fibercolloid solution functioned the best. The 4% STP treated shrimp lost the least amount of moisture during boiling. The 0.5% fibercolloid and 0.5% XG treatment outperformed phosphates in respect to moisture uptake ability. None of the treatments had a major effect on water activity. All treatments were rated similar in consumer sensory acceptability tests except for pectin, which was rated lower by the sensory panel. Overall, polysaccharides were found to be viable alternatives to phosphates.     

Dry Fractionation Methods to Produce Barley Meals Varying in Protein, Beta-Glucan, and Starch Contents

ABSTRACT:  Barley contains several valuable nutrients including beta-glucan (BG), protein, and starch. Each has additional value when concentrated. Dehulled and hulless barleys were sequentially pearled for 1 to 6 cycles, each with 8% removal. The 6 pearled kernels and the initial kernel were subjected to impact or abrasive milling, followed by sieving with a series of U.S. standard sieves. Results of pearling fines show that protein was most concentrated in the outer area, and decreased all the way toward the core area (near 100% surface removal). Starch showed an opposite trend. BG followed the starch trend, but reached a peak at about 60% surface removal. Upon milling and sieving of kernel samples, genotype and particle size had significant effects on nutrient contents in sieved fractions. The pearling cycle had significant effects on protein and starch contents but little effect on BG content, while the milling method had significant effects on protein and BG contents but little on starch content. Abrasive milling produced sieved fractions with much higher variation in protein content than impact milling, but the opposite effect was observed for shifting BG content. Mass frequency influenced more on recovery rates of nutrients than their concentrations in individual fractions. When the recovery rate was also taken into consideration, pearling alone was found to be the most effective way to enrich protein in barley kernels. However, a combination of pearling with the method of milling and sieving was needed for maximally shifting BG and starch contents.
PRACTICAL APPLICATIONS: Although dry fractionation is the method of choice for separating barley into fractions with varying levels of protein, BG, and/or starch, selection of a specific single or combined method is needed for achieving maximum shifts of a particular nutrient. Such information is significant to those who use dry fractionation methods to enrich protein, BG, and/or starch.     

高蛋白全营养液工艺配方优化研究

研究了影响高蛋白全营养液稳定性的因素,确定了加工营养液的最佳工艺和配方。得到的高蛋白全营养液呈淡褐色,均匀,无分层现象,静置一段时间后无上浮,口感良好,无豆腥味。高蛋白全营养液所含各种营养成分比例适当,中链脂肪酸和长链脂肪酸比例合理,可口服或管饲,能满足病人各种营养需要。     

COMPOSITION AND PROPERTIES OF EXTRUDED, TEXTURIZED POULTRY MEAT

Hand deboned leg and thigh tissues from broilers and mechanically de-boned broiler neck meats were extruded and texturized using a dry heat process. During heat processing of all meat tissues, there was a significant (P< 0.05) reduction of moisture content and significant increases in fat and protein levels as heating time increased. Meat strands from the texturization process became firm, possessing structural integrity as determined by the binding strength among meat tissue particles and strand resistance to shearing. Significant (P < 0.05) increases were observed in tissue water-holding capacity and emulsion stabilizing capacity although salt-soluble protein extractability was significantly (P < 0.01) reduced by the heating during texturization     

Methods for accelerating malting,a small scale investigation

It was confirmed that steeping fully after-ripened barley at 25° or 30°c, for various periods, induces different degrees of ‘water sensitivity’. Germination of such warm-steeped grain, set to grow at the steeping temperature, was maximal when the moisture content was about 35%. Sprays of hydrogen peroxide, applied immediately after draining the steeped grain, accelerated the subsequent germination of warm-steeped barley when grown at elevated temperatures. Exceptionally rapid steeping/germination schedules were elaborated, using micromalting techniques. For example, fully mature grain was steeped, (7 h 25°c) to a moisture content of about 36%. All subsequent processing was also at 25°c. After a drain (2 h) the grain was sprayed with a solution of gibberellic acid (0·25 mg/kg) in a dilute solution of hydrogen peroxide (2·5 vol.). Spraying with water was carried out twice more during the germination period to increase the moisture content of the barley to about 44%. The grain was set to kiln at 43°c, 48 h from steep out, that is 55 h from first wetting. Kilning conditions were chosen to allow maximal survival of enzymes. The malt had a hot water extract above 103 lb/Qr (fine grind, on dry matter) and was made at the expense of a 7·5% malting loss. It was acceptable by other analytical criteria. If the second water spray was replaced by a spray of a dilute solution of sulphur dioxide (400 mgjkg) a malt having an extract of 103·5 lb/Qr was obtained with a malting loss of 5·8%, but yielding more soluble nitrogen. The possibility of achieving even shorter processing times, by working at 30°c, was noted.     

Fate of the fusarium mycotoxins,deoxynivalenol, nivalenol and zearalenone,during extrusion of wholemeal wheat grain

In the European Union, deoxynivalenol in cereals and cereal products is controlled by recent legislation with the objective of minimizing consumer exposure to this mycotoxin. Relatively few studies have examined the loss of Fusarium mycotoxins during processing and whether this is accurately reflected by the processing factors. The behaviour of deoxynivalenol, nivalenol and zearalenone during extrusion of naturally contaminated wholemeal wheat flour has been examined using pilot-scale equipment. Factors examined were temperature and moisture content. Concentrations of the three mycotoxins were little changed by extrusion although the amount of deoxynivalenol decreased at the lowest moisture content. However, this effect did not appear to be temperature-dependent, suggesting that the apparent loss is either due to binding or inability to extract the residue. Under some conditions, concentrations of the mycotoxins, particularly nivalenol, were higher after extrusion.     

EFFECT OF STORAGE ON NUTRITIVE VALUE OF FOOD1

With few exceptions, nutrient levels and/or their bioavailability are reduced in foods following harvest, slaughter, or collection. Rate of these losses is usually attenuated by reducing temperature of storage. Initial heat processing to the point of enzyme inactivation, or to the point of microbial sterilization, “stabilizes” the food so that it does not “spoil” but at the same time causes a greater initial reduction in certain nutrients, and a more gradual reduction with extended storage. Initial heat processing and mechanical treatments may also release nutrients so that they become more available, but once released, they are also subject to losses unless stored at low temperatures. Ascorbic acid is undoubtedly the most sensitive to loss and changes to a less active form as the result of time and temperature in storage. In many instances changes in ascorbic acid reflect general changes in quality. Thiamine is the other vitamin which is frequently affected adversely by time and temperature of storage. The A vitamins appear to be lost readily in leafy vegetables, but relatively unchanged in other foods. There is little effect on mineral content of foods, but bioavailability, particularly of iron may be influenced during prolonged storage. Substantial losses in carbohydrates may be encountered as a result of respiratory activity in extended storage at relatively high temperatures. Protein content is rarely affected, but protein availability is readily reduced even in low moisture foods unless they are protected from oxygen and stored at low temperatures. These anticipated changes in nutritive value are of particular significance in nutrient labeling, and must be taken into account when preparing nutrient labels.     

Quality of Whole Lobster (Homarus americanus) Treated with Sodium Tripolyphosphate Before Cooking and Frozen Storage

ABSTRACT: The objective of this study was to determine the effects of pre-rigor treatment of lobster muscle with sodium tripolyphosphate (STP) before cooking, cryogenic freezing, and frozen storage. STP concentrations of 0.1% and 0.3% were prepared in 0.9% saline solution and injected into lobster before processing. Controls were injected with 0.9% saline solution. Lobsters were then steam-cooked, cryogenically frozen, and stored at −15 °C. Chemical and textural analyses were conducted on reheated samples at storage months 0, 2, 4, and 6, and sensory analyses were conducted at months 2 and 6. Cook loss results showed the 0.3% STP-treated lobsters had a 5% significantly ( P 0.05) lower cook loss than the 0.1% STP and control samples. Yield results revealed that STP-treated tails had a 0.7% to 0.8% significantly ( P 0.05) higher meat yield than control samples. Total moisture results showed that STP-treated lobster tail and claw meat had higher total moisture levels compared with control samples at month 6. Sensory results revealed that panelists rated both 0.1% and 0.3% STP-treated lobster tails significantly ( P 0.01) higher for flavor and texture, and significantly ( P 0.001) higher for overall acceptability than control samples at month 6. The results indicated that STP added at low concentrations may extend the shelf life of whole cooked cryogenically frozen lobster, decrease lipid oxidation over frozen storage time, maintain texture, color, and flavor attributes, increase yield, and decrease drip loss.     

Gamma Irradiation Effects on Thiamin and Riboflavin in Beef, Lamb, Pork, and Turkey

A study was made of the loss of thiamin and riboflavin due to gamma irradiation of beef, lamb and pork longissimus dorsi, turkey breast and leg muscles. Thiamin losses averaged 11%/kiloGray (kGy) and riboflavin losses 2.5%kGy above three kGy. The rate of loss of thiamin in beef was higher than that in lamb, pork and turkey leg, but not turkey breast. with losses of 16%/kGy in beef and 8%/kGy in lamb. The rate of thiamin loss was not related to sulfhydryl, protein, moisture, fat or water content, pH or reducing capacity by redox titration. Loss of riboflavin was not different among species. Any detriment from such slight losses would seem to be more than compensated by the advantage of controlling bacteriological contamination by irradiation processing.     

The Effect of Micronization Operational Conditions on the Physicochemical Properties of Navy Beans (Phaseolus vulgaris L.)

Micronization conditions for processing navy beans were evaluated relative to micronizer outlet temperature, final moisture content, hardness, soluble protein, hydration capacity, and density using a full factorial experiment. Processing variables included conveyer bed slope (SL), setting of gas‐air mixture valve (GS) or gas/air ratio, and distance between conveyer bed and infrared radiation source (DS). As SL and the gas/air ratio increased, the final temperature of the micronized navy beans increased but bean moisture content was reduced. The percent soluble protein and hydration capacity also were reduced as SL increased. The contribution of DS to the characteristics of beans micronized under these conditions was minimal. Recommended conditions were best determined based on outlet temperature.     

西门塔尔杂交牛不同部位肉间的差异性

测定雄性西门塔尔杂交牛（西门塔尔牛♀×南阳黄牛♂）的肩肉、霖肉、黄瓜条、臀肉、牛腱和牛腩6 个部位肉的蛋白质、脂肪、水分及胶原蛋白含量、pH值、色差、质构、剪切力以及凝胶乳化特性指标。结果表明：西门塔尔杂交牛的牛腩具有高蛋白、高脂肪、低水分含量等特点,且剪切力较高、蒸煮损失较低;霖肉含高蛋白、低胶原蛋白和低水分含量,保水性与凝胶特性较好,但其脂肪含量较低;臀肉具有较高的弹性、咀嚼性和保水性,但凝胶特性和乳化特性较差;肩肉的硬度、弹性和咀嚼性均适中,保水性较差;牛腱的蛋白含量、脂肪含量、解冻损失较低,凝胶弹性和乳化稳定性好;黄瓜条弹性、嫩度、凝胶保水性和乳化性均较好,但解冻损失较大。上述结果表明,西门塔尔杂交牛不同部位肉的特性有显著差异,不同特性的部位肉适宜的加工方式不同。     

Evaluation of the chemical composition and colour in long‐life tomatoes (Lycopersicon esculentum Mill) dehydrated by combined drying methods

When tomatoes are submitted to treatments of drying, depending on the parameters and methods used, the concentration or degradation of nutrients can occur. The changes in the composition and colour were verified when different drying processes were used. Freeze drying, oven drying, the combination of both and also the effect of the pretreatment (blanching) using steam were studied. The fresh tomato composition was compared with the composition of dehydrated tomato powder. After dehydration, the moisture content reduced 78% from the total initial moisture. In addition, a nutrient concentration was observed with an increase of about 57% of citric acid content and 3% in the pH. The ash content also increased from 0.53% to 8% (15 times) and 60%, the carbohydrates from 3.94% to 60% (15 times) and the proteins were increased from 1% to 11% (10 times). The blanching resulted in different types of changes, such as greater stability for the proteins, carbohydrates, fat, lycopene and β‐carotene.     

YIELD, PROXIMATE COMPOSITION AND MINERAL ELEMENT CONTENT OF THREE CULTIVARS OF RAW AND ROASTED PEANUTS

Yield of kernels, proximate composition (moisture, crude fiber, fat, protein and ash), and content of nine mineral elements–Ca, Mg, P, Na, K, Fe, Cu, Zn and Mn-are reported for three cultivars of peanuts, raw and roasted. Roasting resulted in higher concentrations of all nutrients measured in the peanuts except moisture and sodium, whose contents decreased. Although statistically significant differences in nutrient content were noted among cultivars, these differences were of little practical importance. Data on retentions of proximate components and mineral elements with roasting of peanuts indicate that except for moisture and sodium (which were low) and ash (which was high), retentions were close to 100%.     

不同加工工艺对黑蒜产品品质的影响

黑蒜是一种新型大蒜加工制品,通过不同加工工艺得到两种不同的产品黑蒜1号和黑蒜2号,其中黑蒜1号的生产周期为黑蒜2号的3倍。本研究比较了两种加工工艺对黑蒜基本营养成分、蒜氨酸含量以及自由基清除能力的影响。研究表明:与新鲜大蒜相比,黑蒜的水分含量较少约为40%,湿基中的可溶糖、蛋白质和多酚显著增多(P0.01),蒜氨酸含量减少。而干基中的营养物质除多酚外,其余成分都减少,脯氨酸和精氨酸急剧降低,变异系数分别为1.03和1.12。湿基对OH·的清除能力基本一致,对DPPH·的清除力为新鲜蒜的2倍。黑蒜1号的粗蛋白含量低于黑蒜2号,可溶糖、多酚、蒜氨酸皆高于黑蒜2号,粗蛋白和多酚变异系数达到0.20左右,各组分间存在显著差异(P0.05)。在不同浓度下对自由基清除能力相同,当浓度为0.05 g/m L时,对OH·和DPPH·的清除率达到了90%以上。电子舌可以有效的区别两种产品。     

EFFECT OF RN GENOTYPE ON YIELD AND SENSORY CHARACTERISTICS OF ENHANCED LONGISSIMUS SECTIONS

Pumping treatments with water or 4.5% sodium tripolyphosphate (STP) were evaluated on the fresh longissimus from pigs of different Rendement Napole genotypes. The longissimus muscle (32 RN/rn, 32 rn⁺/rn⁺) was divided into 3 sections and allocated to the: nonpumped, water pumped, and 4.5% STP, treatments. Following aging (14 days) chops were cut, packaged, and frozen. Boneless loin chops were cooked to internal temperatures of either 70C or 80C. Nonpumped loins resulted in the least amount of purge loss, whereas STP loins had the highest raw yield. Pumping loin sections with water and STP increased raw and cooked moisture contents. Pumping with STP increased juiciness and tenderness ratings. Increasing the endpoint temperature decreased juiciness and cooked moisture percentage. Pork from RN/rn⁺ pigs had lower shear force and higher tenderness and juiciness. These data indicate that increasing end point cooking temperature reduced pork palatability while STP pumping and the RN gene improved sensory properties.     

Effect of various additives to marinating baths on some properties of cattle meat

Longissimus dorsi (LD) muscles obtained from young bull carcasses (Holstein Friesian) were marinated, using solutions containing 0.5% sodium tripolyphosphate (STP), 0.5% dicalciumhydrogen phosphate (CHP) and 0.5% citric acid (CA). All solutions, including a blank, contained 2% NaCl. Expressible moisture, cooking loss, marinade uptake, area gain (increase in slice size), colour coordinate values (L*, a*, b*), marinade and meat pH, and the textural properties of samples were evaluated. Marinating with STP and CHP solutions resulted lower cooking losses. Marinade uptake and area gain were lower for control steaks and steaks marinated with the CA solution. The highest lightness was found in steaks marinated with the CA solution. Steaks marinated with STP and CHP solutions were darker. The CA solution resulted in yellowness of steaks. All treatments significantly affected hardness, chewiness and resilience values of steaks. The lowest hardness value was found in steaks marinated with CA. STP and CHP treatments also improved tenderness.     

玉米蛋白粉挤压膨化工艺参数优化研究

以单螺杆挤压膨化机为试验设备对玉米蛋白粉进行膨化试验,运用二次通用旋转组合设计试验方法研究了玉米蛋白粉含水率、膨化机螺杆转速和机筒温度对加工后的玉米蛋白粉持水性的影响。结果表明:影响玉米蛋白粉持水性的主要因素是机筒温度,试验因素主次顺序依次为机筒温度、螺杆转速、物料含水率;较优组合为:物料含水率43%、螺杆转速334r/min、机筒温度157℃。