Wk Of Storage Research Articles

Comparison of Shelf Life of Eggs Coated with Chitosans Prepared under Various Deproteinization and Demineralization Times

ABSTRACTInternal quality of eggs coated with chitosans prepared under various deproteinization (DP at 0, 5, 15 min) and demineralization (DM at 0, 10, 20, 30 min) times was evaluated. Chitosans prepared under DP 0 min/DM 30 min, DP 5 min/DM 30 min, and/or DP 15 min/DM 20 min conditions can be effectively used as an egg‐coating material in preserving the internal quality of eggs compared with chitosan prepared under the DP 15 min/DM 30 min condition. The Haugh unit and yolk index values suggested that the chitosan‐coated eggs can be preserved for at least 2 wk longer than the control noncoated eggs during 5 wk of storage at 25°C.

Quality Measurement of Intact and Fresh‐cut Slices of Fuji, Granny Smith, Pink Lady, and GoldRush Apples

ABSTRACT: Development of fresh‐cut apple products requires consideration of cultivars that store well as both intact and fresh‐cut fruit. We compared the instrumental and sensory quality of 2 apple cultivars, Granny Smith and Fuji, that are used for fresh cutting with 2 new cultivars, Pink Lady and GoldRush, which were considered to have quality characteristics suitable for fresh cutting. Firmness, titratable acidity (TA), soluble solids content (SSC), and aromatic volatile concentration were measured in intact fruit of the 4 cultivars during 12 mo storage in air at 0 °C and during 3 wk storage at 5 °C as fresh‐cut slices. After 1 wk storage as fresh‐cut slices, sensory evaluations for acceptability of flesh and peel appearance, flavor, texture, and overall eating quality were performed. During storage, GoldRush apples maintained > 80 N firmness, approximately 17% SSC, > 0.5% TA, and had high aromatic volatile production, that is, maintained quality better than the other cultivars. The quality and shelf stability of GoldRush slices were also as good as or better than slices from the other cultivars, whereas Granny Smith slices generally rated lower than the other cultivars. The acceptability of flavor, texture, and overall eating quality of GoldRush slices was as good as that for Pink Lady and Fuji. The quality of GoldRush apples can be maintained throughout the year in refrigerated air storage and still remain suitable for fresh‐cut processing. The results indicate that GoldRush and Pink Lady are 2 promising new, high‐quality apple cultivars for fresh cutting. Keywords: fresh‐cut fruit, Malus × domestica, postharvest quality, respiration rate, shelf life

Aroma Analysis of Light-Exposed Milk Stored With and Without Natural and Synthetic Antioxidants

The effect of antioxidants, added in a single initial dose or in weekly additions to extended shelf life milk, was evaluated over 6 wk of lighted storage at 4°C. Light-induced oxidation was measured by determining pentanal, hexanal, heptanal, and 1-octen-3-ol contents. Weekly addition of a combination of butylated hydroxyanisole and butylated hydroxytoluene (100 mg/kg of milk fat, each) maintained heptanal content of milk at levels comparable to light-protected milk, whereas an initial single addition of α-tocopherol significantly decreased hexanal content over the first 4 wk of storage. Odor-active compounds associated with light-induced oxidation included 2,3-butanedione, pentanal, dimethyl disulfide, hexanal, 1-hexanol, heptanal, 1-heptanol, and nonanal. The addition of butylated hydroxyanisole and butylated hydroxytoluene in a single initial addition resulted in decreases in pentanal and hexanal odor, but not in heptanal and 1-heptanol odor, whereas the addition of α-tocopherol and ascorbyl palmitate decreased pentanal and heptanol odor, but not hexanal and heptanal odor.

Autoxidation of cod liver oil with tocopherol and ascorbyl palmitate

AbstractCod liver oil (CLO) with no added antioxidants (REF), 200 mg/kg ascorbyl palmitate (AP), and/or 800 mg/kg tocopherol concentrate (TOH) were stored in sealed bottles with a small headspace of air at 25°C in the dark. A binary mix of TOH +AP affected the sensory perception of CLO by leading to a more grass/cucumber‐like and less herring oil‐like impression, whereas TOH alone had no effect. This was caused by the different influence of the antioxidants with regard to formation of volatile oxidation products. TOH+AP promoted formation of, e.g., hexanal, 2‐hexenal, and 2,6‐nonadienal and inhibited formation of, e.g., 2,4‐heptadienal. TOH affected the proportions of trans, cis‐and trans,trans‐2,4‐heptadienal that were formed and inhibited formation of, e.g., 1‐penten‐3‐ol, whereas formation of acetic acid and some other volatiles was inhibited by both antioxidants. The total amount of volatiles increased during the experiment, and with REF were significantly higher (P<0.05) than with TOH. The PV increased during the first 2 wk of storage. PV levels were in the order of TOH>REF>TOH+AP. The observed effects could partly be explained by hydrogen donation from TOH to peroxyl radicals, but the mode of action for AP was unclear.

Effect of Intermittent Curing on Mandarin Quality

ABSTRACT: The effect of an intermittent curing treatment (IC), 2 cycles of 18 h at 38 °C, to control decay during shelf life of mandarins was studied. The effectiveness of IC to control blue mold development in artificially inoculated Clemenules fruits (Citrus reticulata Blanco cv. Nules) was complete with 0% decay after 1 wk storage at 20 °C. Nonsignificant differences were found in soluble solids, color, and firmness. By the end of shelf life, a significantly lower acidity and a higher weight loss (4.75%) was observed in IC-treated fruits. Ascorbic acid levels decreased in all stored fruits along shelf life, with slightly lower values in IC-treated mandarins than in control fruits. Sugars and organic acids content were not affected by curing. Though slight increases in ethanol and some detrimental terpene oxidized compounds were found, not off-flavor development was observed. This, intermittent curing treatment seems to be a feasible treatment to control blue mold development during shelf life of Clemenules mandarin fruits, without impairing quality parameters such as color, firmness, sugars, and organic acids contents, vitamin C content, and aroma.

Suppressive Effect of Functional Drinking Yogurt Containing Specific Egg Yolk Immunoglobulin on Helicobacter pylori in Humans

Helicobacter pylori is a human pathogen that infects over 50% of the population worldwide. It is the most important etiologic agent of gastroduodenal ulcers and malignancies. Helicobacter pylori urease enzyme is considered the main factor for the organism's colonization in the gastroduodenal mucosa. Hens immunized with the purified urease produce a highly specific anti-H. pylori urease immunoglobulin (IgY-urease) in their egg yolks. Immunoglobulin Y-urease was stable at 60 to 65°C for 30min and at pH 4.0 for 7h. Its activity was lost at 80°C for 20min and at pH 2 for 4h. Specially designed functional drinking yogurt containing Lactobacillus acidophilus and Bifidobacterium spp. with 1% egg yolk IgY-urease was produced commercially. Immunoglobulin Y-urease activity showed stability in the product up to 7 d, and then decreased to 85% after 3 wk of storage. A clinical study was conducted to determine the effectiveness of IgY-urease yogurt to suppress infection in humans. Forty-two volunteers who tested positive for H. pylori using a 13C-urea breath test were recruited. A total of 450mL of IgY-urease (test group) or IgY-urease–free yogurt (control group) was consumed in 150-mL portions 3 times daily for 4 wk. Volunteers were tested after 2 and 4 wk; urea breath test values significantly decreased in the test group compared with the control group. The results indicate that suppression of H. pylori infection in humans could be achieved by consumption of drinking yogurt fortified with IgY-urease.

Utilization of Pork Collagen Protein in Emulsified and Whole Muscle Meat Products

ABSTRACT: Effects of pork collagen in emulsified and whole muscle products were evaluated. Eight frankfurter treatments (0%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, and 3.5% pork collagen) and 4 ham treatments (0%, 1%, 2%, and 3% pork collagen) were formulated. Frankfurters and hams were evaluated for cooked yields, purge, color, texture, and sensory characteristics. Incorporation of pork collagen at 1% and above significantly (P < 0.05) increased cooked and chilled yields in frankfurters but did not have any effect in hams. Purge was significantly (P < 0.05) reduced in both frankfurters and hams after 4 wk of storage. Sensory difference testing showed no significant difference up to 2% usage level of pork collagen in both frankfurters and hams (P > 0.05).

Shelf-life and Microbiological Profiler of Chicken Wing Products Following Sous vide Treatment

Chicken wings were vacuum-packaged and cooked (sous vide) at 75 and 90 C until the internal o temperature reached 73.8 C was reached. The cooked samples were stored at 2 and 7 C, separately. The o o TBA values, aerobic plate count, aerobic and anaerobic plate counts and Warner-Bratzler (WB) shear force of the samples were evaluated weekly for 7 wk. The sous vide treatment chicken wings had lower TBA values, aerobic and anaerobic plate counts throughout the 7 wk of storage when compared with the control. The sous vide treatment did not affect the WB shear force of chicken wings. At 2 C, the sous vide cooked o chicken wings had a shelf life of at least 7 wk. Results demonstrate that sous vide treatment was an effective method to prevent lipid oxidation during storage and enhance shelf life of chicken wing products.

Survival and Activity of Probiotic Lactobacilli in Skim Milk Containing Prebiotics

ABSTRACT: Seven strains were cultured anaerobically at 37 °C for 48 h in 12% (w/v) reconstituted skim milk containing 5% (w/v) Hi‐maize, lactulose, inulin, or raftilose. Their viability was determined before and after 4 wk of storage at 4 °C. Doubling time (Td) was also determined. Concentrations of acetic and lactic acids produced during fermentation and storage were determined. The Td ranged from 301 to 751 min. In general, the viability of lactobacilli after storage was greatest with inulin. The pH after storage in skim milk ranged from 4.34 (for ASCC 1520 with raftilose) to 4.10 (for ATCC 15820 with inulin). Survival of lactobacilli in prebiotic was strainspecific but in general their survival was enhanced.

Effect of Sweet Humectants on Stability and Antimicrobial Action of Sorbates

ABSTRACT: The effect of glucose or polyols on sorbate stability and on its antimicrobial action were studied in aqueous systems (pH 3.0). All humectants promoted preservative degradation, but polyols decreased browning development. Depression of water activity did not inhibit the growth of Zygosaccharomyces bailii, but xylitol increased the lag phase and decreased the growth rate and the stationary phase level. Sorbate minimum inhibitory concentration (MIC) concerning Z. bailii growth acquired slightly lower values (0.020% w/w) when sorbitol or xylitol were present for systems with water activity of 0.971. The residual level of the preservative after 3 wk of storage at 35 °C was smaller than the MIC for all studied systems with the exception of the humectant‐free system.

Functional Properties of Cholesterol-removed Compound Whipping Cream by Palm Oil

The present study was carried out to examine the changes in functional properties of cholesterol-removed compound whipping cream made by β-CD treated cream and palm oil. Six different ratios of cream to palm oil (10:0 as control, 9:1, 8:2, 7:3, 6:4, and 5:5, v/v) were tested. The overrun percentage increased with an increased amount of palm oil. When the ratio of cream to palm oil was 10:0 (control), the overrun was 130%, which was significantly lower than other ratios reached to 150%. Foam instability was measured as 3. 1 ml defoamed cream in control, however, the value of foam instability decreased with an increase of palm oil addition. The TBA value of cholesterol-removed compound whipping cream increased from 0.08 to 0.13 with no addition of palm oil during 4 wk storage. When the ratio of cream to palm oil was 5:5, TBA value increased dramatically at 3 wk and thereafter. Among sensory characteristics, texture value increased with higher amount of palm oil, however, flavor and overall preferences were opposite. Above results indicated that partial substitution of palm oil in manufacture of cholesterol-removed compound whipping cream resulted in a stable foam development with little adverse effect on flavor and lipid oxidation during storage. The present study showed a possible application in manufacture of cholesterol-removed compound whipping cream, which may be effective in other foods.

Comparison of peanut meal and soybean meal as protein supplements for laying hens

Peanut protein is severely limiting in threonine and has been used to create threonine deficiency in animals. The availability of purified threonine at low cost raises the possibility of economically using peanut meal (PNM) and threonine combinations in poultry diets. An experiment was conducted to compare corn and PNM based diets to corn and soybean meal (SBM) based diets at three protein levels (16, 18.5, and 21%) in diets for 22-to-34-wk-old commercial Leghorns. Birds were housed two per cage with four cages per replicate and six replicates per treatment. Feed consumption, egg production, and feed per dozen eggs were almost identical for PNM (93.8 g/hen per d, 92.2 eggs per 100 hens/d, and 1.22 kg/dozen) and SBM (93.7 g/hen per d, 92.2 eggs per 100 hens/d, and 1.22 kg/dozen). Dietary protein level had no consistent effect on any of these parameters but did significantly improve body weight gains and egg weights (1.2 to 2.5 g/egg). PNM-fed hens laid slightly smaller eggs during the first 6 wk (P<0.05), but there were no egg size differences during the last 6 wk of the experiment (P>0.14). PNM-fed hens laid eggs with better interior quality at 26 and 30 wk of age. After 2 wk of storage, Haugh units remained better for eggs from hens fed PNM than SBM when kept refrigerated (4 degrees C; P<0.05) or at room temperature (20 degrees C; P<0.10). Egg specific gravity was slightly lower for hens fed PNM. It is concluded that PNM is an excellent ingredient for laying hen diets.

Effect of 1‐Methylcyclopropene on the Quality of Fresh‐cut Apple Slices

ABSTRACT: The objective of this project was to treat fresh‐cut apple slices with the ethylene inhibitor 1‐methylcyclopropene (1‐MCP) to retard ethylene‐induced deterioration and senescence and to prolong the shelf life of such products. Intact Braeburn and Pacific Rose apples were treated at different times with 1‐MCP, cut, and stored at 0 °C. Samples were analyzed initially and then weekly for ethylene, respiration, flesh firmness, tissue color, titratable acidity, and soluble solids content during 5 wk of storage. 1‐MCP treatment was effective in reducing ethylene production, respiration, and loss of firmness and color of slices when applied to whole apples directly after harvest. Total sugar and acidity levels were not affected significantly.

Antioxidative properties and enzymatic synthesis of ascorbyl FA esters

AbstractEfficient synthesis of unsaturated FA esters of ascorbic acid is possible with only a small excess of one of the reactants in t‐amyl alcohol using Candida antarctica lipase as biocatalyst. Using free acids, we obtained yields that were comparable to yields reached using vinyl‐activated acyl donors (71, 80, and 86% yields of esters with FA excesses of 1∶1, 1∶1.5, and 1∶2, respectively). As very low water activity is needed to achieve sufficiently high yields of product, molecular sieves were used to improve the ascorbyl ester yields. Ascorbyl oleate is more amorphous and has a much lower m.p. and lower enthalpy of fusion than ascorbyl palmitate. This leads to a higher solubility of ascorbyl oleate in oil, resulting in an increased antioxidant effect compared to that of the palmitate. In an accelerated storage test using deodorized rapeseed oil, samples incubated with ascorbyl palmitate showed noticeable oxidation after 1 wk of storage, whereas samples incubated with ascorbyl oleate displayed negligible oxidation for 9 and 4 wk at 30 and 40°C, respectively.

Effects of Oral Administration of Specific Antibodies to Rainbow Trout Oncorhynchus mykiss

AbstractA new product called oralized fish serum concentrate (OFSC) was evaluated for a possible effect against various bacterial pathogens in rainbow trout. The OFSC produced from immune trout sera was found to contain fully functional antibodies and complement component C3. The antibodies detected in the serum concentrate were specific to Vibrio anguillarum (O1 and O2) and Aeromonas salmonicida, which had been used for vaccination of the fish prior to serum collection. The functionality of the specific antibodies in OFSC was not reduced after 6 wk storage at ‐20 C, 5 C, and 20 C. The serum was mixed with commercial trout feed and used for feeding rainbow trout fry (first feed period). After oral delivery of OFSC to rainbow trout for 1 mo, samples of gut content and gut tissue contained functional antibodies. In gutted fish no functional antibodies were found. This suggests that antibodies from OFSC are unable to be transferred across the gut wall in a functional state. Oral administration of OFSC did not increase survival of rainbow trout in an immersion challenge with Vibrio anguillarum.

Oxidative stability and sensory and functional properties of eggs from laying hens fed supranutritional doses of vitamins E and C

This study evaluated the effects of two dietary doses of vitamins E and C supplemented separately and together, on the content of vitamin E in the yolk, on the lipid stability of fresh and stored eggs, and on their sensory and functional properties. Hy-Line Brown hens (n = 216) received a basal diet for 8 wk supplemented with 100 or 200 mg DL-alpha-tocopheryl acetate (E100 or E200, respectively)/kg, 500 or 1,000 mg ascorbic acid (C500 and C1000, respectively)/kg, or 100 mg DL-alpha-tocopheryl acetate plus 500 mg ascorbic acid (E100+C500)/kg, whereas the control group received no supplementation. Fresh eggs and eggs stored 30,60, and 90 d at 4 C or stored 28 d at room temperature were analyzed for vitamin E content and TBA-reactive substances (TBARS). We also evaluated functional properties of fresh and cooked eggs and sensory properties of boiled and scrambled eggs. The yolk content of vitamin E depended on the level of dietary addition and decreased after 90 d of storage at 4 C or after 28 d at 25 C. Vitamin supplementation had no effect on fresh or refrigerated eggs, whereas 4 wk of storage at room temperature increased TBARS in the control and the group supplemented with the highest doses of vitamins. Ascorbic acid improved Haugh units and elasticity of albumen gels, whereas cohesiveness and hardness of yolk, albumen and whole-egg gels were not affected by dietary treatment. Panelists were not able to distinguish treated eggs from control eggs.

Physicochemical Properties and Microbial Stability of Reduced‐Fat Chinese‐Style Sausage Stored under Modified Atmosphere Systems

ABSTRACT: Physicochemical properties and microbial stability of reduced‐fat Chinese‐style sausages packaged with various modified atmosphere packaging (MAP) systems were evaluated. With the exception of VAC (vacuum) treatment, the TBARS (thiobarbituric acid‐reactive substances) values increased with increasing storage time. Treatments of C100 (100% CO2), C80 (80% CO2/20% N2), and C20 (20% CO2/80% N2) were higher in TBARS values than VAC and N2 (100% N2) after 2 wk of storage. The numbers of total plate counts, psychrotrophs, total anaerobes, or lactic acid bacteria increased slightly, though statistically insignificant, during storage, while N2 was numerically the lowest and VAC was intermediate. Vacuum packaging was more effective than other MAP in maintaining lipid and microbial stability of reduced‐fat Chinese‐style sausage. Keywords: reduced‐fat, Chinese‐style sausage, MAP, storage stability, vacuum packaging

Encapsulation of sea buckthorn kernel oil in modified starches

AbstractEncapsulation of CO2‐extracted sea buckthorn kernel oil and the stability of the products were investigated. Maltodextrin and an emulsifying starch derivative were used for encapsulation by spray drying. Both shell materials significantly increased the storage stability of sea buckthorn kernel oil, even though in maltodextrin capsules 10% of the total oil was extractable from the surface of the capsule. The cornstarch sodiium octenyl succinate derivative capsules contained essentially no surface oil. After 9 wk storage at controlled conditions (20°C, RH 50%), PV of the unencapsulated oil was above 90 meq/kg, whereas in the encapsulated oils, the PV was still around 20 meq/kg. The PV of the encapsulated oil was dependent on the storage conditions. A small increase in temperature (from 20 to 25–30°C) and a significant increase in humidity (from RH 50 to RH 50–70%) decreased the stability of capsules. This was associated with the physical state of the microcapsule matrix and may be linked with glass transition of the wall polymers.

Pathogen Reduction and Quality of Lettuce Treated with Electrolyzed Oxidizing and Acidified Chlorinated Water

ABSTRACT: The efficacy of electrolyzed oxidizing (EO) and acidified chlorinated water (45 ppm residual chlorine) was evaluated in killing Escherichia coli O157:H7 and Listeria monocytogenes on lettuce. After surface inoculation, each leaf was immersed in 1.5 L of EO or acidified chlorinated water for 1 or 3 min at 22 °C. Compared to a water wash only, the EO water washes significantly decreased mean populations of E. coli O157:H7 and L. monocytogenes by 2.41 and 2.65 log10 CFU per lettuce leaf for 3 min treatments, respectively (p &lt; 0.05). However, the difference between the bactericidal activity of EO and acidified chlorinated waters was not significant (p &gt; 0.05). Change in the quality of lettuce subjected to the different wash treatments was not significant at the end of 2 wk of storage.

Effect of Various Dairy Packaging Materials on the Shelf Life and Flavor of Pasteurized Milk

Milk from three different dairies (each a separate trial: 1, 2, and 3) was standardized to 2% fat and pasteurized at 92.2, 84.0, and 76.4°C (temperatures 1, 2, and 3, respectively) for 25s and packaged into six different packaging boards, [standard (A) milk boards with standard seam; juice boards with standard (B) and J-bottom (D) seams; barrier boards with standard (C) and J-bottom (E) seams; and foil (F) boards with J-bottom seam], resulting in 18 different treatments. Standard plate count (SPC) was used to test for microbial quality, and taste a panel was employed for flavor acceptability and difference on the milk stored at 6.7°C at 1, 2, 3, and 4 wk. Statistical analysis of taste panel data showed that the flavor of milk samples A2, B2, and D2 deteriorated faster than the blind control (freshly high temperature, short time pasteurized low fat milk processed at 80.6°C for 25s). The flavor of milk packaged in standard (A) and juice (B and D) boards deteriorated at a faster rate than milk packaged in barrier (C and E) and foil (F) boards. Microbial counts showed that milk samples stored at 6.7°C in trials 2 and 3 produced high SPC at wk 3 (ranges of bacteria in cfu/ml for trial 2: 9.9 × 101 –1.8 × 106 and trial 3: 2.5 × 105 –5.5 × 108). In trial 1, high SPC began at wk 4 (9.9 × 101 – 5.5 × 105 cfu/ml). Milk processed at 76.4°C had the lowest bacterial growth rate, and milk processed at 84.0°C had the highest bacterial growth rate. Different boards had no effects (P>0.05) on the bacterial growth rates. It appeared that the lower the SPC of the raw milk, the slower the bacterial growth rate after 2 wk of storage. Milk samples stored at 1.7°C maintained low SPC at wk 4, with counts of 0 to 40 cfu/ml for trial 2 and 0 to 200 cfu/ml for trial 3.