散沫花提取物复合明胶膜对冷链运输及放置过程中牛肉品质的影响

本研究调查了以墨鱼皮明胶和散沫花提取物（HAE）作为天然保鲜剂制备出的功能性涂膜对模仿冷链运输及零售1、3、6和8 d牛肉贮藏损失、颜色、菌落总数、脂质氧化以及高铁血红蛋白、血红素铁和游离氨基酸含量的影响,综合评价了散沫花提取物复合明胶膜对牛肉冷藏保鲜效果的的影响。结果表明,与未涂膜样品相比,涂膜处理有效防止了水分的流失和高铁肌红蛋白的形成,保持了肉样的持水性和颜色特性（P<0.05）。随着放置期的延长,HAE+明胶膜通过在贮藏期减少脂质氧化程度、菌落总数和嗜冷菌数,显著延长了肉的货架期（P<0.05）。此外,根据游离氨基酸含量,涂膜处理可以显著降低蛋白水解过程的速率,而未涂膜处理的样品水解速率更快（P<0.05）。主成分分析表明,样品颜色的变化与pH、血红素铁含量、脂质氧化以及微生物繁殖存在高度相关性,而HAE+明胶涂膜良好地抑制了这些因素的发展。因此,HAE+明胶涂膜可以作为有效的活性保鲜方式,用于肉类的冷藏保鲜。     

Characterization of Edible Active Coating Based on Alginate–Thyme Oil–Propionic Acid for the Preservation of Fresh Chicken Breast Fillets

Chicken meat presents serious problems of processing and storage. Edible coatings are used commercially to improve the shelf life of fresh foods. The aim of this study is to develop an effective antimicrobial edible coating to improve the shelf life and safety of fresh chicken meat. The effect of propionic acid and thyme essential oils as antimicrobial and antioxidant compounds incorporated into alginate‐based edible coating was evaluated. Physical, antimicrobial and sensorial analyses were performed in coated and uncoated samples. Sensorial analysis showed no significant differences between coated and uncoated samples, which do not influence the buying decisions of consumers. The pH of the meat surface, color and sensorial analysis changed during storage time, showing similar behavior between coatings, the principal parameters to determine the shelf life of this product were weight loss and microbiological deterioration, where coatings had different behaviors. The selected coating increased the shelf life by about 33% with the lowest dehydration.     

Antioxidant properties of plum concentrates and powder in precooked roast beef to reduce lipid oxidation

Boneless beef roasts (Semimembranosus + Adductor) were injected (20%) with a brine containing (1) no plum ingredient (control), (2) 2.5 or 5% fresh plum juice concentrate (FP), (3) 2.5 or 5% dried plum juice concentrate (DP), or (4) 2.5 or 5% spray dried plum powder (PP). Whole roasts were cooked, vacuum-packaged and stored at <4.0 °C for 10 wk. At 2 wk intervals, evaluations were performed on sliced product to determine vacuum-packaged purge, Allo-Kramer shear force, lipid oxidation (TBARS), color space values, and sensory attributes. All plum ingredients reduced TBARS values and had minimal effects on tenderness, sensory characteristics, color and appearance. Small changes in purge, color values, TBARS and some sensory properties were found during storage. These results indicate that 2.5% FP or DP could be incorporated into precooked beef roasts to reduce lipid oxidation and potentially, warmed-over flavor (WOF).     

Effects of Antimicrobial Edible Coating of Thymol Nanoemulsion/Quinoa Protein/Chitosan on the Safety,Sensorial Properties,and Quality of Refrigerated Strawberries (<Emphasis Type="Italic">Fragaria × ananassa</Emphasis>) Under Commercial Storage Environment

The effectiveness of the edible coating with thymol nanoemulsion on the safety, sensorial properties, and quality of refrigerated strawberries was investigated under commercial storage conditions. Spontaneous emulsification was used to obtain the thymol nanoemulsion that was included on quinoa protein/chitosan coatings. During the entire storage time, strawberries coated with thymol-antimicrobial packaging had a lower fungal and yeast load compared with the controls (uncoated and coated with quinoa protein/chitosan). The flavour and aroma of the coated strawberries was initially affected, although this sensory appreciation was improved from the fifth day of storage and showed similar scores than the controls, and presenting better aroma score at day 12 of storage. Furthermore, the shelf life of the thymol nanoemulsion-coated strawberries increased in 4 days, unlike that in the both controls. Further, the application of these biocoatings on strawberries significantly decreased the weight loss relative to that in the control, during 16 days of storage at 5 °C and 90% relative humidity, and did not alter the quality parameters (pH, titrable acidity, and percentage of soluble solids). These results suggest that the application of thymol/nanomulsion-loaded edible films is an effective strategy to increase the shelf life of highly perishable products such as strawberries.     

Selected Quality Characteristics of Fresh‐Cut Sweet Potatoes Coated with Chitosan during 17‐Day Refrigerated Storage

ABSTRACT: Selected quality characteristics of fresh‐cut sweet potatoes (FCSP) coated with chitosan were evaluated during 17‐d refrigerated storage. The FCSP cubes were coated with a solution (1%, w/v) of chitosan having 470 or 1110 kDa. Color (L*, a*, b*) values of uncoated and chitosan‐coated FCSP during storage were generally affected by storage time as well as coating treatments (P < 0.05). No significant changes in color lightness (L*) of 470 kDa‐coated FCSP were observed during the 17‐d storage. During days 3 to 17, 470 kDa‐coated FCSP had significantly higher redness (a*) and yellowness (b*) values than did uncoated and 1110 kDa‐coated FCSP. Texture firmness of uncoated and chitosan‐coated FCSP exhibited minimal changes during the 17‐d storage. Although actual weight loss values (%) of uncoated and chitosan‐coated FCSP were not significantly different at day 17, the weight loss difference (%) between day 3 and day 17 for uncoated FCSP (3.02%) was slightly higher compared to those (2.24% to 2.26%) of chitosan‐coated FCSP. The initial total aerobic count was 4.7 log₁₀ CFU/g which then gradually increased to 8.54 and 9.67 log₁₀ CFU/g after 17 d of storage for 470 kDa‐coated and uncoated FCSP, respectively. After day 6, the total aerobic counts of uncoated FCSP were higher than those of 470 kDa‐coated FCSP. The yeast and mold count of chitosan‐coated FCSP was about 2.5 log₁₀ CFU/g at day 17. Overall, consumers could not differentiate between 470 kDa‐coated FCSP at day 17 and uncoated FCSP at day 0.     

Evaluation of Fresh Vacuum-Packaged Beef Steaks Coated with an Acetylated Monoglyceride

Fresh beef loin steaks were coated with 3% (w/w) acetylated monoglyceride (DFG), vacuum-packaged and held at 2 ± 2°C for weekly evaluation during a 49-day storage period. When compared to control steaks, DFG had little effect on lean color, surface discoloration, overall appearance, moisture, pH, and sensory characteristics. DFG maintained an acceptable fat color longer and tended to reduce purge and microbial counts (aerobic, APT, and coliform) during storage. After 49 days, Lactobacillus cellobiosis was the dominant microorganism on treated and control steaks. The uncharacteristic aroma, oily coating and cost of application might outweigh the benefits derived from the use of DFG as an edible coating on steaks.     

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.     

Antioxidant properties of plum concentrates and powder in precooked roast beef to reduce lipid oxidation

Boneless beef roasts (Semimembranosus + Adductor) were injected (20%) with a brine containing (1) no plum ingredient (control), (2) 2.5 or 5% fresh plum juice concentrate (FP), (3) 2.5 or 5% dried plum juice concentrate (DP), or (4) 2.5 or 5% spray dried plum powder (PP). Whole roasts were cooked, vacuum-packaged and stored at <4.0 °C for 10 wk. At 2 wk intervals, evaluations were performed on sliced product to determine vacuum-packaged purge, Allo-Kramer shear force, lipid oxidation (TBARS), color space values, and sensory attributes. All plum ingredients reduced TBARS values and had minimal effects on tenderness, sensory characteristics, color and appearance. Small changes in purge, color values, TBARS and some sensory properties were found during storage. These results indicate that 2.5% FP or DP could be incorporated into precooked beef roasts to reduce lipid oxidation and potentially, warmed-over flavor (WOF).     

Improving quality of fresh‐cut mango using polysaccharide‐based edible coatings

This study was aimed at evaluating the effect of coatings with alginate (AL), pectin (PE), carboxymethyl cellulose (CMC) or chitosan (CH) on microbial stability, physicochemical attributes, total phenolics and carotenoids content, antioxidant capacity and sensory properties of fresh‐cut mango during 14 days at 4 ± 1 °C. Coated fresh‐cut mango kept microbial counts below 6 logs CFU g^?1, being CH‐coated fresh‐cut mango those that exhibited the lowest microbial counts (1 log CFU g^?1) along entire storage. AL, PE and CMC coatings maintained yellow colour of fresh‐cut mango throughout storage. AL and CH coatings, which have different monomers in their chain, improved the content of antioxidant compounds in fresh‐cut mango as related to uncoated. AL‐coated fresh‐cut mangoes were the toughest, among those coated, during 14 days. The highest consumer acceptance was achieved in AL (90.2%) coated fresh‐cut mango. CH would be the most suitable coating to extend the quality of fresh‐cut mango throughout storage.     

Chitosan coating minimises eggshell breakage and improves egg quality

The interior quality of eggs, shell impact strength, and consumer perception of eggs coated with chitosan containing an organic acid (acetic, lactic and propionic) were evaluated. Uncoated eggs had the highest albumen pH and lowest albumen viscosity. The viscosity of eggs coated with chitosan and lactic or propionic acids were the highest. Chitosan coating also improved shell strength with chitosan + lactic acid being the best coating in this regard. The colour of shell and yolk as measured by lightness (L*), a*, b*, chroma and hue of coated and uncoated eggs were not significantly different but the difference was detected in the colour of albumen, which is an effective indication of freshness and egg quality. Based on sensory evaluation, consumers could not differentiate coated eggs from uncoated eggs; thus the general acceptability of the coated eggs was the same as uncoated eggs. This study shows a great potential of using chitosan and lactic acid mixture as a coating material for egg coating to extend the shelf life. It has no effect on consumer acceptability of the product. Copyright © 2007 Society of Chemical Industry     

Development of Shelf-stable Intermediate-moisture Meat Products Using Active Edible ChitosanCoating and Irradiation

Shelf‐stable intermediate‐moisture (IM) meat products were developed using a combination of hurdles such as reduced a_w, active edible coating of chitosan, and irradiation. Chitosan prepared from chitin had a viscosity of 16 c P, molecular weight of 17.54 kDa, and a degree of deacetylation (DD) of 74%. The nitrogen content of the chitosan was estimated to be 7.56%. The antioxidant activity of chitosan increased upon irradiation without significantly affecting its antimicrobial property. The effect of irradiated chitosan coating in terms of its antimicrobial and antioxidant properties in IM meat products immediately after irradiation and during storage was assessed. The a_w of meat products such as mutton sheek kababs and streaky bacon was first reduced to 0.85 ± 0.02. The products were then coated with chitosan and irradiated (4 kGy). No viable bacteria or fungi were detected in chitosan‐coated, irradiated products. In contrast, IM meat products that were not subjected to gamma radiation showed visible fungal growth within 2 wk. The chitosan‐coated products showed lower thiobarbituric acid‐reactive substances (TBARS) than the noncoated samples for up to 4 wk of storage at ambient temperature. The studies thus clearly indicated the potential use of chitosan coating for the preparation of safe and stable meat products.     

含肉桂精油的壳聚糖涂层对冷藏草鱼片的保鲜作用

通过在草鱼片上添加含肉桂精油(CIN)的壳聚糖(chitosan,Ch)涂层,研究含肉桂精油的壳聚糖涂层对草鱼片(4±1)℃ 冷藏16 d期间品质的影响.涂层分别采用质量浓度20 g/L Ch和Ch+CIN[质量浓度20 g/L Ch+1.5％(体积分数)CIN]配方溶液,对未添加涂层和添加不同配方涂层鱼片样品的微生物...     

Study of Spray System Applications of Edible Coating Suspensions Based on Hydrocolloids Containing Cellulose Nanofibers on Grape Surface (<Emphasis Type="Italic">Vitis vinifera</Emphasis> L.)

An edible coating is a useful technology to preserve fruit quality by covering them with a protective layer which improves the appearance and provides a semipermeable barrier for gases and water vapor transfer, allowing extension of their shelf life. In this study, edible coatings based on hydroxypropyl methyl cellulose, k-carrageenan, glycerol, and cellulose nanofibers were formulated. The operational conditions of the spray system were studied to obtain a coating with optimal adhesion on grape (Vitis vinifera L.) surface. Furthermore, the physico-chemical properties of grapes covered with edible coatings were evaluated during refrigerated storage. A full factorial 2³ experimental design was applied, where liquid suspension flow (1–5 L h^?1), air pressure (50–200 kPa), and height of impact (0.3–0.5 m) were evaluated as independent variables, whereas the percentage of coating and thickness of coating was the response variables. Both mechanical and physico-chemical properties were evaluated during 41 days in both coated and uncoated grapes as shelf life criteria. Throughout the storage time, noticeable changes in pH and total soluble solids were not found in grapes covered with edible coatings and they showed the highest stability for the evaluated mechanical properties. Moreover, coated grapes showed final weight loss and water vapor permeability values of approximately 30 and 34% lower, respectively, than uncoated grapes, suggesting a shelf life extension.     

Quality and microbial safety of ‘Fuji’ apples coated with carnauba-shellac wax containing lemongrass oil

A carnauba-shellac wax (CSW)-based nanoemulsion containing lemongrass oil (LO) was prepared using high pressure homogenization. ‘Fuji’ apples were coated with the CSW/LO nanoemulsion and the coated apple samples were compared with uncoated apple samples with respect to quality and microbial safety for 5 months. During storage, the hardness of the uncoated apples decreased by 3.3 N, and the weight loss was 7.7%. In contrast, the hardness of the coated apples did not change, and the weight loss was 5.2%. Titratable acidity and total soluble solids were not significantly different between coated and uncoated apples. The apples coated with the CSW/LO solution had the best sensory appreciations. After 5 months of storage, the population of total aerobic bacteria on the coated apples was decreased by 1.4 log CFU/g compared with the uncoated apples. In addition, the population of yeast and molds on the uncoated apples was 2.2 log CFU/g after 5 months of storage, whereas yeast and molds were not detected on the coated apples. The CSW/LO coating can improve the quality of ‘Fuji’ apples during storage.     

In vitro antimicrobial effects of Myristica fragrans essential oil on foodborne pathogens and its influence on beef quality during refrigerated storage

Nutmeg (Myristica fragrans) seed was subjected to the hydro-distillation method to extract its essential oil (NEO). Its main constituents were α-pinene (20.16%), sabinene (14.45%), and β-pinene (13.26%) with great antimicrobial and antioxidant actions. A novel edible coating was then fabricated based on the sage seed mucilage (SSM) and NEO, to ameliorate the quality and shelf-life of beef slices. The NEO-loaded SSM coating was able to significantly decrease the population of total viable count, Escherichia coli, Staphylococcus aureus, psychrotrophic bacteria, and fungi. Moreover, lipid oxidation of beef slices was remarkably suppressed upon the application of bioactive NEO-loaded SSM edible coating, as compared with the control by Day 6. The coated beef sample, especially NEO-rich SSM coated ones perceived a higher consumer acceptance and firmness than the SSM coated and noncoated samples. The SSM edible coating containing NEO could therefore have the potential to control the growth of pathogenic microorganisms and lipid oxidation, and to improve the color stability and sensory properties of meat and meat products.     

Evaluation of ionically cross‐linked chitosan coating aimed at eggs' protection

Chitosan films were prepared in combination with sodium tripolyphosphate (TPP) cross‐linking and were investigated on the prevention for trans‐contamination and preservation of egg quality. The study demonstrated that chitosan films significantly decrease Salmonella enteritidis settlement (from 7% to 0.5%) and penetration of eggshells (from 93 to 58% of penetrated eggs). Due to neither bactericidal action nor bacteriostatic effect of films was observed by the enumeration method, films seem to act as a physical barrier. Moreover, results showed potential applications of coating with properties to preserve the internal quality of eggs: the weight loss is not significantly affected (weight loss remains 4% average after 23 days) and the Haugh unit is significantly higher (26 and 37 were evaluated for eggs uncoated and coated, respectively) in the presence of chitosan film.     

淀粉-壳聚糖可食性复合薄膜保鲜布林的研究

本文主要研究了不同种类的淀粉与壳聚糖复合所形成的被膜对于布林的保鲜效果。分别用木薯淀粉,土豆淀粉,玉米淀粉与壳聚糖制成不同涂膜液对布林进行涂膜处理,在常温(15～25℃)下储藏。涂膜的布林在贮藏期间,其水分损失,硬度,可溶性固形物,总酸度的变化均小于对照组, 并且可延长保质期3～7d。就不同的淀粉成分而言,对于布林的保鲜作用,土豆淀粉-壳聚糖复合薄膜的保鲜作用最佳,玉米淀粉-壳聚糖复合薄膜的作用优于木薯淀粉-壳聚糖复合薄膜。     

Influence of Whey Protein Composite Coatings on Plum (Prunus Domestica L.) Fruit Quality

This study evaluated the quality of plums (Prunus domestica L.) coated with whey protein isolate (WPI) and WPI composite coatings containing 5 or 10% (w/w) flaxseed oil blended with beeswax. WPI and 10% lipid composite coatings were less susceptible to crack, flake, and blister defects during the 15 days storage at 5°C compared to the 5% lipid formulation. The firmness of plums, determined by the penetration force using a 10-mm probe, was not significantly affected by the coating types except for the WPI-coated samples, which showed a significantly higher penetration force because of the higher strength for WPI film. Mass loss of plums during storage was substantially reduced because of coating, especially when coatings of higher lipid content were used. This was consistent with the water permeability for the standalone films, which decreased considerably when flaxseed and beeswax were added. The incorporation of lipid phase to WPI also significantly weakened oxygen barrier and mechanical properties. Migration of plasticizer and lipid phase to the film surface was observed during water vapor permeability tests, especially when the films were exposed to elevated humidity conditions. Overall, sensory evaluation showed that the coated plums were more acceptable than the uncoated controls.     

Effect of silver carp (Hypophthalmichthys molitrix) muscle hydrolysates and fish skin hydrolysates on the quality of common carp (Cyprinus carpio) during 4 °C storage

Silver carp (Hypophthalmichthys molitrix) skin and muscle were hydrolysed, respectively, and then used as part of an edible coating to preserve fish. The effects of muscle and skin hydrolysates as edible coatings for shelf life extension of common carp (Cyprinus carpio) were evaluated over 18 days at 4 °C, by comparing these two treatments, a chitosan coating with muscle hydrolysate, chitosan alone, and an untreated control. All coatings were made up with 5% glycerol. The quality of the carp was assessed by using total volatile basic nitrogen (TVB‐N), total viable counts (TVC), thiobarbituric acid (TBA) and K value. Compared with the control group, the rate of increase in TVB‐N, TVC, TBA and K value of carp coated with fish skin hydrolysates, fish muscle hydrolysates and chitosan added to fish muscle hydrolysates were lower. According to the total viable counts, the storage life of fish with fish skin hydrolysates coatings and chitosan added fish muscle hydrolysates coatings were 16 days, 2 days longer than those with the chitosan coatings and twice as long as the control group.     

PET trays coated with Citrus extract exhibit antioxidant activity with cooked turkey meat

A natural Citrus extract with potential antioxidant activity was evaluated as an ingredient for the production of active food packaging. The extract, in methanol, was sprayed onto the surface of polyethylene terephthalate (PET) trays. For comparison, a second set of trays were prepared using α-tocopherol as the coating. The effectiveness of the two types of packaging in delaying lipid oxidation in cooked turkey meat slices, stored at 4 °C over 4 days, was compared using 2-thiobarbituric acid-reactive substances (TBARS) and hexanal assays. TBARS and hexanal values, for meat stored on the Citrus extract coated trays, were significantly lower (P < 0.01) than those of meat stored on uncoated (control) trays while α-tocopherol coated trays exhibited no significant effect compared to control trays (P > 0.05). The effectiveness of the Citrus extract coating, compared to the α-tocopherol coating, was attributed to its higher surface roughness, demonstrated by optical profilometry, and the higher level of release (solubility) of the antioxidant in water.