Effect of Potassium Sorbate on Refrigerated Storage of Vacuum Packed Scallops

Scallops (Pecten alba) were packaged aerobically, vacuum packaged, treated with 0.1% K-sorbate then packaged, or vacuum packaged and frozen. The initial flora was predominantly Vibrio which grew well in the aerobic packs (? 10⁸ c.f.u./g after 6 days at 4°C) and in the vacuum packs (? 10⁷ c.f.u./g after 6 days 4°C). The microbial counts in the sorbate-treated scallops were low (? 10³ c.f.u./g) after 6 days at 4°C and rose to 10⁵ c.f.u./g by 22 days, remaining at this level until the experiment ended after 48 days. Extensive use of taste panels as an evaluative tool enabled construction of odor and flavor profiles which showed clearly the nature of the changes that occurred during storage. The sorbate-treated scallops stored for up to 28 days at 4°C remained as acceptable as the frozen controls.     

Potassium Sorbate Effect on Pigment Concentration of Refrigerated Beef

The influence of potassium sorbate (SorK) on the relative concentrations of myo (Mb), oxi (MbO₂,) and metamyoglobin (MetMb) of raw beef samples wrapped in plastic films of differcnt gaseous permeability was determined at 0°C and 4°C. Diffuse rcflectance spectrophotometry was applied to determine muscle pigmcnts concentrations. Kinetics constants for Mbo₂, and MetMb production during acrobic storage (polyethylene film) were statistically analyzed and compared with constants corresponding to sterilc and untreated meat. Influence of vacuum storage time, temperature and SorK levels on oxygenation capacity of samples packaged in EVA-SARAN-EVA was studied considering losses of cnzymatic activity and microbial growth. Shelf life of vacuum-packaged beef trcatcd with SorK solutions was significantly increased without affecting oxygenation capacity; use of SorK in meat wrapped in high permeability films was not convcnient since MetMb accumulation was faster than in untreated muscle.     

Potassium Sorbate Inhibition of Microorganisms Growing on Refrigerated Packaged Beef

The influence of potassium sorbate concentration (27–1325 ppm of sorbic acid) on the growth of natural flora in raw beef samples wrapped in plastic films of different oxygen permeability was studied at 0° and 4°C. Changes in aerobic plate counts, Pseudomonas spp., Brochothrix thermosphacta, Lactobacillus spp., Enterobacteriaceae and yeasts were monitored. Sorbate treatment effect on percentage increment of lag phase and reduction of growth rate during exponential phase for the different microorganisms were analyzed and antimicrobial action was evaluated by the Inhibition Index. A significant increase in the time to reach aerobic counts of 10^6.5 CFU/cm² was observed at low storage temperatures and pH values in vacuum packaged treated samples.     

Color Stability of Edible Coatings During Prolonged Storage

ABSTRACT: The yellowing rates of edible coatings were determined at 23, 40, and 55 °C at 75% relative humidity (RH). Whey protein isolate (WPI) coatings had lower yellowing rates than whey protein concentrate (WPC) and the same rates as shellac coatings. Hydroxypropyl methylcellulose (HPMC) coatings had the lowest yellowing rates. Zein coatings became less yellow during storage; however, their color was still pronounced. Activation energies and Q₁₀ values for the yellowing of whey protein coatings were similar to those previously reported for the browning of whey powder. The results indicate that WPI coatings can be used in place of shellac coatings when low-color development is desired. WPC coatings can be used to tailor color development of a food.     

Nanoencapsulation Approach to Improve Antimicrobial and Antioxidant Activity of Thyme Essential Oil in Beef Burgers During Refrigerated Storage

In this study, thyme essential oil (TEO) loaded chitosan nanoparticles (CS-NP-TEO) are prepared by a two-step process including oil/water emulsion and ionic gelation. Five batches of burgers were prepared by following formulation: control (without any TEO), F-0.05-TEO (0.05 % of free TEO), F-0.1-TEO (0.1 % of free TEO), E-0.05-TEO (0.05 % of encapsulated TEO), E-0.1-TEO (0.1 % of encapsulated TEO), and AA-0.05 (0.05 % of ascorbic acid). All samples treated with TEO significantly reduced the population of investigated microbial counts (P?<?0.05) compared to the control during 8 days of storage. At the end of storage, E-0.05-TEO and E-0.1-TEO, presented, respectively, 2.2 and 3 log cycles reduction of Enterobacteriaceae, along with 3.1 and 3.7 log cycles reduction of Staphylococcus aureus. Oxymyoglobin content and redness values reduced with the increase of storage time for all samples. However, AA-0.05 and E-0.1-TEO samples were more efficient at inhibiting discoloration in comparison with E-0.05-TEO and burgers treated with free TEO after 6th day of storage. A significant improvement (P?<?0.05) in the reduction of thiobarbituric acid reactive substances (TBARS) amount was found for all TEO treated burgers in comparison to control samples after 8 days chilled storage. According to the results of sensory analyses, F-0.1-TEO and AA-0.05 samples at 4 days and F-0.05-TEO sample at 8 days of storage were rejected by assessors and considered as an unacceptable case. On the basis of our results, the encapsulation of TEO in chitosan nanoparticles may be a promising technology for the control of undesirable microbial, chemical, and sensorial changes in meat products.     

Properties of Low-Fat Ground Beef Containing Potassium Lactate During Aerobic Refrigerated Storage

Low-fat patties containing water, carrageenan, encapsulated salt and hydrolyzed vegetable protein (carrageenan-based patties) with 0, 1, 2 or 3% potassium lactate were compared to low-fat all-beef patties with no additives. Carrageenan-based patties had enhanced (P<0.05) sensory properties (juiciness, tenderness, mealiness and beef flavor intensity) compared to all-beef patties. The bacterial populations of low-fat, carrageenan-based patties did not differ (P<0.05) from low-fat all-beef patties. Bacterial growth in low-fat, carrageenan-based patties was reduced through the use of 2 or 3% potassium lactate with no deleterious effects on the sensory properties of the low-fat, ground beef. However, low-fat, carrageenan-based patties underwent greater (P<0.5) discoloration and lipid oxidation during aerobic refrigerated storage than all-beef patties.     

Edible Coating Effects on Storage Life and Quality of Tomatoes

Tomatoes at breaker and pink stage maturities were coated with comzein film. Color, weight and firmness changes and sensory quality were compared with noncoated tomatoes during storage at 21°C. Corn-zein fdm delayed color change and loss of firmness and weight during storage. Shelf life was extended by 6 days with film coatings as determined by sensory evaluation.     

Sorbic Acid and Potassium Sorbate Permeability of an Edible Methylcellulose-Palmitic Acid Film: Water Activity and pH Effects

The apparent permeability constants for potassium sorbate and sorbic acid through an edible film composed of methylcellulose and palmitic acid (weight ratio 3:1) were evaluated as a function of water activity (a_w) and pH. For films with thickness 55–66 μm, potassium sorbate permeability increased from 2.3 × 10^?10 to 2.0 × 10^?8 (mg/sec cm²)(cm)/(mg/mL) as a_w increased from 0.65 to 0.80. Films were not stable at a_w levels above 0.80. Permeability of the film to sorbic acid at a_w 0.8 decreased from 3.3 × 10^?8 to 9.1 × 10^?10 (mg/sec cm²)(cm)/ (mg/mL) as pH increased from 3 to 7. At pH 3 the undissociated acid was 97.5% and at pH 7 it was 0.4%.     

Antimicrobial Activity of Butylated Hydroxyanisole, Tertiary Butylhydroquinone, and Potassium Sorbate in Combination

Butylated hydroxyanisole (BHA), tertiary butylhydroquinone (TBHQ), and potassium sorbate, alone and in combination, were tested for antimicrobial activity against Staphylococcus aureus and Salmonella typhimurium in trypticase soy broth. Concentrations of the antimcrobials which resulted in 0-50% growth lnhibition of the test organisms after 72 hr at 32°C were used in combination. Sorbate-BHA and sorbate-TBHQ combinations caused a 12 hr delay in growth initiation of S. aureus. No delay in growth initiation was found with BHA-sorbate combinations against S. typhimurium, but all combinations had synergistic antimicrobial activity against the: microorganism. TBHQ showed little or no effect on growth of S. typhimurium.     

次氯酸钠、山梨酸钾、丙酸钙三因素对板栗贮藏性的研究

采用三元二次正交旋转组合设计,研究了次氯酸钠、山梨酸钾、丙酸钙在常温下对板栗好果率的影响,建立并分析了板栗好果率对三因素的函数模型。结果表明,三因素对板栗好果率的影响大小依次为丙酸钙〉山梨酸钾〉次氯酸钠;常温贮藏一个月要达到55％以上的好果率,三因素的最佳组合为次氯酸钠的浓度11．4％-19．5％,山梨酸钾的浓度2．67％-3．99％,丙酸钙的浓度1．09％-2．71％。     

可食性复合涂膜保鲜剂对延长鲜切苹果货架期的研究

本文主要研究了可食性涂膜剂与抗褐变剂复配后对鲜切苹果的保鲜效果。研究表明:25℃条件下,苹果切块经卡拉胶(0.5%)涂膜剂和乳清浓缩蛋白WPC(5%)涂膜剂处理后,其呼吸强度可分别降低5%和20%。在可食性涂膜剂中添加不同的抗褐变剂对苹果切块有良好的护色效果,添加1%CaCl2可增加产品的硬度,同时这些复合保鲜剂可提高苹果切块的感官指标和抑制微生物繁殖,而5%WPC涂膜液+1%CaCl2+1%抗坏血酸复合液浸泡苹果切块,3℃条件下贮藏2w后保鲜效果最佳。     

Viability and Activity of Bifidobacteria During Refrigerated Storage of Yoghurt Containing Mangifera pajang Fibrous Polysaccharides

Abstract: The viability and activity of Bifidobacterium pseudocatenulatum G4, B. longum BB 536 and yoghurt cultures (Lactobacillus delbrueckii ssp. bulgaricus and Streptococcus thermophilus) were studied in yoghurt containing 0.75%Mangefira pajang fibrous polysaccharides (MPFP) and inulin. Growth of probiotic organisms, their proteolytic activities, the production of short chain fatty acids (lactic, acetic and propionic) and the pH of the yoghurt samples were determined during refrigerated storage at 4 °C for 28 d. B. pseudocatenulatum G4 and B. longum BB 536 showed better growth and activity in the presence of MPFP and inulin, which significantly increased the production of short chain fatty acids as well as the proteolytic activity of these organisms. Practical Application: This is the first study reported on produce synbiotic yoghurt as a functional food for specified health uses contains bifidobacteria and M. pajang fibrous polysaccharides. M. pajang fibrous polysaccharides can be used as a prebiotic particularly in dairy products to increase the viability and activity of bifidobacteria which can be used as probiotic to exert health benefit to the human by yoghurt that is considered common use in society; thus, the benefits of synbiotic yoghurt are readily accessible to the member of society.     

Antifungal Coatings on Fresh Strawberries (Fragaria × ananassa) to Control Mold Growth During Cold Storage

ABSTRACT: Chitosan (2%) -based or hydroxypropyl methylcellulose (HPMC) (1%) -based coatings were applied on fresh strawberries to evaluate their antifungal efficacies against Cladosporium sp. and Rhizopus sp. Potassium sorbate (PS) was also incorporated into coating formulas to evaluate any additional inhibitory effects on mold inhibition. Strawberries were inoculated with Cladosporium sp. or Rhizopus sp. at a level of approximately 10³ log colony-forming units (CFU) /g, coated with 2% chitosan, 2% chitosan containing 0.3% PS, or 1% HPMC containing 0.3% PS, and stored at about 5°C and about 50% RH up to 23 d for enumeration of mold, yeast, total aerobes, and coli forms. To assess antifungal activity of the coating materials in vitro, coating solutions were embedded into agar plates and the diameters of radial mold growth were measured after inoculation. In addition, weight loss of coated strawberries and water vapor permeability of the coatings were measured. No significant combined inhibitory effects between chitosan and PS on fungal growth on fresh strawberries were detected. However, significant combined inhibition activity was observed in in vitro testing when PS was formulated into chitosan. Antifungal activity of chitosan against Cladosporium sp. and Rhizopus sp. was not affected by the autoclaving process of coating solutions. Coating treatment also reduced total aerobic count, coliforms, and weight loss of strawberries during storage. Hence, chitosan can be used as a natural antimicrobial coating on fresh strawberries to control the growth of fungi, thus extending shelf-life of the fruits.     

Potassium Sorbate Permeability of Methylcellulose and Hydroxypropyl Methylcellulose Coatings: Effect of Fatty Acids

Surface microbial stability is a major determinant of the shelf life of refrigerated meat products. Surface microbial growth has also been noticed in intermediate moisture foods exposed to temperature fluctuations. One solution to this problem is to apply edible coatings to the food surface which control diffusion of antimicrobial agents into the food. Films with such properties were identified using a permeability cell. Methyl- and hydroxypropyl methylcellulose mixed with lauric, palmitic, stearic and arachidic acid significantly lowered the potassium sorbate permeation rate relative to cellulose ether films containing no fatty acids. Permeability determinations at 5, 24, 32 and 40°C showed excellent agreement with the Arrhenius activation energy model for the permeation process.     

Lipid Addition to Improve Barrier Properties of Edible Starch-based Films and Coatings

ABSTRACT: Effects of formulation (lipid presence, type of starch, and plasticizer) on microstructure, water vapor (WVP) and gas (GP) permeabilities of films and coatings were analyzed. Plasticizer was necessary to maintain film and coating integrity and to avoid pores and cracks. Films made from high amylose starch showed lower WVP and GP than regular corn starch films; permeabilities of films with sorbitol (20 g/L) were lower than those with glycerol. The addition of 2g/L sunflower oil to the formulations decreased WVP of starch-based films; X-ray diffraction and Differential Scanning Calorimetry experiments demonstrated that films with plasticizer and lipid showed lower crystalline-amorphous ratio compared to films without additives. Microstructural observations helped explain the decrease of the film permeabilities during storage.     

Acetic Acid, Formic Acid, and Potassium Sorbate as Preservatives for Short Term Storage of Bovine Hides

Total numbers of aerobic microorganisms, Gram negative bacteria, Clostridium perfringens, coagulase positive staphylococci, and yeasts and molds were monitored during storage of segments of bovine hides. The preservatives tested were acetic acid, formic acid, and potassium sorbate. Potassium sorbate at any concentration tested did not control adequately any group of microorganisms monitored. Acetic and formic acids at all concentrations tested, significantly inhibited growth of all groups of microorganisms. At the highest concentration tested (0.67M) not only did the formic acid inhibit growth of microogramisms, but it had a lethal effect on all groups monitored except yeasts and molds. Formic acid was a better preservative than acetic acid. Neither formic nor acetic acid inhibited growth of yeasts and molds to the same extent as the other groups monitored.     

Effect of Hydroxypropyl Methylcellulose-Lipid Edible Composite Coatings on Plum (cv. Autumn giant) Quality During Storage

ABSTRACT 'Autumn Giant' plums were coated with edible hydroxypropyl methylcellulose-lipid composite coatings. The coatings consisted of beeswax or shellac, at 2 lipid content levels (20% and 60% dry basis). Weight loss of coated plums decreased as lipid content increased. No differences on weight loss were observed between uncoated and 20% lipid-coated plums, indicating that the natural waxes of plums are as effective as coatings having 20% lipid. Water-dipped plums experienced the highest weight loss. Fruit texture was not affected by coating after short-term storage at 20 °C. However, for prolonged storage at 20 °C, the coatings significantly reduced texture loss and internal breakdown compared to uncoated and water-dipped plums.