Antioxidant activity and properties of gelatin films incorporated with tea polyphenol‐loaded chitosan nanoparticles

BACKGROUND: Gelatin film is widely used for the protection of food quality. In order to improve its antioxidant activity, natural antioxidant tea polyphenol‐loaded chitosan nanoparticles (TPCN) were prepared and incorporated into gelatin film. The antioxidant effect of TPCN against the oxidation of fish oil was investigated, as well as the release of TP from nanoparticles in the film. RESULTS: The incorporation of TPCN greatly decreased the tensile strength and oxygen permeability but increased the water vapour permeability and affected the transparency of gelatin film. Scanning electron microscopy images indicated that extensive interference was embedded with TPCN in the film microstructure. The peroxide value of fish oil packaged with films incorporated with TPCN was lower than that of fish oil packaged with control films during the incubation period. The radical‐scavenging activity of films incorporated with TPCN was higher than that of control films, and increasing radical‐scavenging activity of the former was observed during the storage period. CONCLUSION: The antioxidant activity and properties of gelatin film were affected by TPCN incorporation and storage time. Also, the oxidation of fish oil was retarded. The addition of TPCN could improve the antioxidant activity of gelatin film, and the release of TP from nanoparticles in the film was achieved during the storage period. Copyright © 2009 Society of Chemical Industry     

Application of laminated and metalized films to prolong the shelf life of dried barberries

Barberry is a nutritional and therapeutic crop mostly dried and consumed in bulk. However, the lack of proper packaging leads to the decline of many of its valuable properties. The aim of this study was to investigate the effect of different packaging films on barberries properties during storage. 150 g of freshly dried barberries were kept for 6 months at 25 °C within different packaging materials: (i) low-density polyethylene (LDPE); two laminated layers film including LDPE and polyethylene terephthalate (PET) with a total thickness of (ii) 45 μm (LDPE/PET-45) and (iii) 60 μm (LDPE/PET-60); (iv) oriented polypropylene (OPP); (v) three laminated layers film of OPP (3OPP); (vi) three laminated layers film including LDPE, metalized PET and PET (LDPE/mPET/PET); and (vii) four laminated layers film including LDPE, PET, aluminum foil and PET (LDPE/PET/Al/PET). After six months, the least change in moisture content, the lowest loss of DPPH scavenging capacity (97.9%), the minimum overall color difference, and the least increase in acidity (39.3%) were related to barberries packaged in the LDPE/PET-45 film. This is while the lowest loss of ascorbic acid (99.8%) and anthocyanin (62.8%) contents and the minimum microbial deterioration were related to the LDPE/PET-60 film. On the other hand, the LDPE/PET/Al/PET film entailed the lowest barberry weight loss (0.67%) and the minimum increase in firmness (40.7%), while the 3OPP film providing the best preservation of phenolic compounds. In conclusion, it seems two laminated layers films composed of LDPE and PET are appropriate for the preservation of dried barberries during storage.     

Development of an Active Packaging Film Based on a Methylcellulose Coating Containing Murta (<Emphasis Type="Italic">Ugni molinae</Emphasis> Turcz) Leaf Extract

A new active packaging film based on murta leaf extract was elaborated. The extract was incorporated into a methylcellulose layer which was coated on a low-density polyethylene (LDPE) film. Its antioxidant effectivity, antimicrobial activity, and physicochemical properties were evaluated. The active film was able to keep its antimicrobial and antioxidant properties for at least 60 days. During this time, the growth of Listeria (L.) innocua was reduced by 2 log cycles and free radical formation could be inhibited by about 90 % for films stored under light and dark conditions. The active coating on the LDPE film did not affect the thermal and water vapor transmission properties; however, slight changes in the mechanical, color, and optical properties were observed. Finally, a sensory analysis showed that active coating did not change the flavor and odor properties of a fatty food packed inside the active material. This suggests that this active packaging film could be used to extend the shelf-life of packaged food.     

模拟油罐储藏大豆油氧化稳定性研究

以过氧化值、酸值、p-茴香胺值和氧化稳定性指数(OSI)为评价指标,模拟油罐储藏,通过正交试验探讨了温度、含水量、氮气量、储油罐的表面积/体积关键影响因素,在储藏5个月内对成品大豆油储藏期氧化稳定性的影响.结果表明,在大豆油储藏过程中,温度对油脂的氧化稳定性的影响比较显著,其次是氮气量、含水量和储油罐的表面积/体积.由于受外界环境和自身结构的影响,大豆油氧化是一个复杂的过程,因此,为了控制成品大豆油具有较好的氧化稳定性,成品大豆油应在较低的温度(25℃)、适量的含水量(0.02％～0.05％)、充足的氮气(100％)和较大的表面积/体积条件下储藏.     

Storage studies of tomato and bell pepper using eco‐friendly films

Tomato (Lycopersicon esculentum) and bell pepper (Capsicum annuum), packaged in cartons (approximately 0.35 kg per box) covered with either eco‐friendly chitosan film or synthetic petroleum‐based low‐density polyethylene (LDPE) film, were stored at room temperature (27 ± 1 °C) and 65 ± 3% relative humidity (RH). Fruits were withdrawn periodically and changes in physico‐chemical, instrumental and sensory characteristics were analysed. During storage, oxygen levels showed only marginal changes, while CO₂ levels showed a gradual increase, especially so in LDPE film‐covered cartons. The fresh weight loss, colour, firmness, formation of defective spots and shrivelling showed greater changes for unpackaged fruits as well as for those in LDPE film‐covered cartons, in comparison with fruits stored in chitosan film‐covered cartons, which retained many of the desirable attributes. Principle component analysis of data from sensory or instrumental sensory analyses indicated segregation of samples stored under different conditions with respect to both desirable and undesirable attributes. The fruits showed greater deterioration, including the loss of characteristic bell pepper odour, when packaged in cartons covered with LDPE films, while those packaged in chitosan film retained more of the desirable quality attributes for a longer period. Copyright © 2006 Society of Chemical Industry     

Development of a novel controlled-release nanocomposite based on poly(lactic acid) to increase the oxidative stability of soybean oil

A poly(lactic acid) (PLA)-based nanocomposite active packaging was developed for the controlled release of tert-butylhydroquinone (TBHQ) antioxidant. The PLA-based active films were loaded with only TBHQ (3% wt) or a mixture of modified cellulose nanofibre (MCNF) (8% wt) and TBHQ (3% wt) to obtain active and nanocomposite active films, respectively. Release studies indicated that the release rate of TBHQ in 95% ethanol simulant was significantly decreased by the addition of MCNF. Moreover, the presence of MCNF diminished the increasing effect of temperature on the release rate as when storage temperature increased from 4°C to 40°C. The diffusion coefficient (D) for PLA-TBHQ and PLA-MCNF-TBHQ films increased from 6.75 and 4.34 × 10^?8 cm² s^?1 to 19.85 and 8.49 × 10^?8 cm² s^?1, respectively. Diffusion of TBHQ to soybean oil was enough to delay the induction of the oxidation of soybean oil stored for 6 months in contact with PLA-based films. Antioxidative activity of PLA-based active films considerably increased with increasing storage time as indicated by the increase in 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and the oxidative stability index (p < 0.05). This study demonstrates that effective controlled release antioxidant packaging could be obtained by using MCNF nanofiller, which leads to prolonged activity and an extended shelf-life in fatty foods.     

Original article: Incorporations of blueberry extracts into soybean‐protein‐isolate film preserve qualities of packaged lard

The effect of blueberry‐extract incorporation into soybean‐protein‐isolate edible film on the quality of packaged lard was compared with vitamin E or butylated hydroxyl anisole (BHA) incorporations individually during the storage at 36 °C and relative humidity of 40% for 5 weeks. Blueberry‐extract incorporations into soybean‐protein‐isolate film showed a greater tensile strength, lower water vapour permeability and lower oxygen permeability than vitamin E or BHA incorporations individually. On the other hand, the antioxidant capacity of soybean‐protein‐isolate film incorporated with the blueberry extract was greater than that incorporated with vitamin E and similar to that incorporated with BHA. Moreover, soybean‐protein‐isolate film incorporated with the blueberry extract showed a greater capacity to delay the lard hydrolysis than that incorporated with BHA, and a similar capacity to that incorporated with vitamin E. Consequently, blueberry‐extract incorporations into soybean‐protein‐isolate film not only improved mechanical and barrier properties, but also delayed the oxidation and hydrolysis of packaged lard. Therefore, blueberry‐extract incorporations into soybean‐protein‐isolate films have potential as a packaging material which will preserve the qualities of stored lard.     

Antioxidant ability of BHT‐ and α‐tocopherol‐impregnated LDPE film in packaging of oatmeal

Cereals in general, and particularly oatmeals, are considered rather sensitive to oxidation owing to their relatively high fat content. The addition of antioxidants can sometimes prolong the shelf‐life of products. The aim of the present study was to investigate how the rate of lipid oxidation of a packaged oatmeal product was affected by the nature and level of antioxidants incorporated in an LDPE film structure. The stability of the product, which was determined by hexanal analysis using GC–MS and by electronic nose analysis, showed very small variations over the chosen storage period. No oxidation, as determined by hexanal levels in the oatmeal, was initiated during storage, but small variations in volatile profile were seen among the samples analysed by the electronic nose. The product stored in the BHT‐impregnated LDPE film had undergone the least change during 10 weeks of storage at 20 °C. α‐Tocopherol‐impregnated LDPE film did not appear to prolong the shelf‐life of the oatmeal at all. © 2000 Society of Chemical Industry     

Extension of the shelf-life of foal meat with two antioxidant active packaging systems

The objective of this study was to investigate the effect of antioxidant active system on physico-chemical properties, the microbial counts, lipid and protein stability and the sensory properties' changes of foal steaks during storage time. The experimental packaging systems were: (i) control group was packaged without active film, (ii) ATOX group was packed with active film containing a 2% of an oregano essential oil and (iii) ATGT group was packed with active film containing 1% of a green tea extract. Samples were filled with 80% O₂/20%CO₂ atmosphere and displayed under illumination at 2 °C for 14 days. Microbial populations were reduced up to 3.60 log CFU/g on day 14 of storage with the most pronounced effect being achieved by green tea film. Active films with oregano led to a significant (P < 0.001) inhibition of metmyoglobin formation. The use of oregano active film resulted in a decreased lipid and protein oxidation of foal steaks. Active films with oregano were significantly (P < 0.05) more efficient than those with green tea extended fresh odour and colour from 7 to 14 days compared to the control.     

Active Banana Flour Nanocomposite Films Incorporated with Garlic Essential Oil as Multifunctional Packaging Material for Food Application

Active plasticized banana flour nanocomposite film (APBNF) incorporated with a different garlic essential oil (GO) content was formed using a solution casting to determine the film properties prior to the investigation of its effectiveness to preserve the roasted peanut quality. The GO concentration was positively correlated with the ultraviolet (UV) light barrier property and antioxidant activity indicating the ability to protect the packed food product from lipid oxidation. Additionally, incorporation of 1 mg/mL GO into APBNF showed the highest antioxidant activity and completely inhibited the growth of Aspergillus flavus. Fourier-transform infrared spectroscopy confirmed the functional group interactions between the film matrix and GO which act as an antioxidant and antimicrobial agent. Thus, APBNF incorporated with 1 mg/mL GO as an active packaging to preserve the quality of roasted peanuts was investigated comparing with a commercial plastic packaging of polyethylene terephthalate/low-density polyethylene (PET/LDPE; PET). The shelf life estimation of roasted peanuts packed in both packaging materials (APBNF and PET) based on the peroxide value (PV) was similar at high storage temperature (45 °C). Therefore, APBNF shows a multifunctional primary food packaging to maintain the quality of roasted peanuts or oily food products.     

Postharvest Quality of Fresh-Cut Carrots Packaged in Plastic Films Containing Silver Nanoparticles

Active food packaging containing antimicrobial additive goes beyond traditional functions of packaging, once it can extend food shelf life maintaining its quality, safety and reducing postharvest losses by controlling food spoilage. Among several antimicrobial additives employed in polymeric films for packaging, metallic nanoparticles outstand due to its facility for synthesis, low-cost of production, and intense antimicrobial properties. In this work, extruded plain films of low-density polyethylene (LDPE) containing silver nanoparticles (AgNPs) embedded in SiO₂ and TiO₂ carriers (namely MS and MT, respectively) were produced and used as active packaging for maintaining the physicochemical and microbiological quality of carrots (Daucus Carota L. cv. Brasília). The neat (LDPE) and composite films containing MS and MT were characterized by scanning electron microscopy and permeability to oxygen and used for packaging fresh-cut sliced carrots stored at 10 °C for 10 days. After the storage time, the physicochemical properties of carrots were characterized, while the antimicrobial properties of films and AgNP migration were investigated. Our results revealed that both MT and MS packages showed antimicrobial activity even for films containing low concentration of AgNP. In addition, AgNP antimicrobial activity demonstrated to be carrier-dependent, once MT-LDPE showed improved performance compared to MS-LDPE. Regarding the physicochemical properties of packaged carrot, lower soluble solids and weight loss and higher levels of ascorbic acid were observed for carrots packaged with MT-LDPE films (compared to MS-LDPE), leading to a better postharvest quality conservation. Such differences observed in physicochemical properties of carrots are related to the distinct antimicrobial and film permeability properties for each composite film. In addition, under the conditions employed in this study, AgNP migration from the packages to fresh-cut carrot was not observed, which is highly desirable for food packaging safety, indicating the potential of such active packages for food preservation application.     

Effects of initial oxygen concentration and oxygen-barrier property of film on fat oxidation rate of packed cookies

Oxygen concentration in packs of cookies is one of the key factors that impacts on fat oxidation. The aim of this study was to investigate the influences of initial oxygen concentration (IOC) in packs and oxygen-barrier performance of packaging film on the fat oxidation rate of cookies. One batch of cookies was packed in high-barrier material PET/AL/ONY/PE bag with a condition of vacuum-packaging (IOC: 1.8%) and modified atmospheres (IOC: 3.5%, 10.3%, 20.9%, 65.5%), respectively; the other batch of cookies was packed with four films of different oxygen transmission rate with air filled in the packs. All samples were stored under the condition of dark, 40 °C and a relative humidity of 50% for more than 30 days, measuring the peroxide values (POV) of cookies during the storage. The results indicated that the fat oxidation rate increased with the increase in IOC in packs and oxygen transmission rate of the packaging films. High concentration of initial oxygen has a significant impact on the fat oxidation in packed cookies, which was not notable under low IOC and was effectively delayed under vacuum packaging. Besides, Logarithm of POV and store time under different IOC and packaging films had a relationship which successfully fitted by linear regression under the same temperature and relative humidity, and a linear correlation between the fat oxidation rate of the cookies and IOC was developed.     

Characteristics of moisture-absorbing film impregnated with synthesized attapulgite with acrylamide and its effect on the quality of seasoned laver during storage

Moisture-absorbing film impregnated with synthesized attapulgite with acrylamide (ATPGAA) was developed. The effects of ATPGAA concentrations of 0.5%, 1%, 2%, and 4% (w/w) in a linear low-density polyethylene polymer (LLDPE) matrix on the film properties were determined by measuring the physical properties, the oxygen and water vapor barriers, and moisture absorbency. The 4% ATPGAA film had high moisture absorbing efficiency. A packaging system fabricated from ATPGAA-impregnated films was applied to a dried-seasoned laver to evaluate its change in quality during storage. Seasoned laver packaged with ATPGAA-impregnated films had significantly greater crispness in texture and a lower peroxide value during storage than that packed with LLDPE film. The surface color of the seasoned laver packaged by ATPGAA-impregnated films was more stable than the control film. This study shows that moisture-absorbing films could serve as a packaging system to improve the storage quality of moisture-sensitive products.     

Development of antimicrobial polyolefin films containing lauroyl arginate and their use in the packaging of strawberries

Low-density polyethylene (LDPE) films were supplemented with lauroyl arginate ethyl (LAE) and characterized for physical, mechanical and antimicrobial properties as well as their use for fresh ‘Sulhyang’ strawberries packaging. LAE powder was added into the LDPE films at 0, 1, 3, 5, and 10% (w/w) and assessed for physical properties, gas permeation, thickness and color values. The results showed that incorporation of LAE into the LDPE matrix did not affect film thickness and color. The thermal stability of the LAE/LDPE film decreased with increasing concentrations of LAE. The LAE/LDPE film exhibited a rough surface and compact structure. Tensile strength were affected by addition of LAE on the other hand value of elongation at break were increased. The LAE/LDPE containing 5 and 10% LAE showed significant antimicrobial properties against mycelium growth. Further, 5 and 10% LAE/LDPE films were used for storage study and it showed that incorporation of LAE into LDPE film was an effective method for maintaining the quality of strawberries. Films containing LAE were very effective at reducing the total weight loss, maintaining firmness, and reduced fungal decay compared to the control strawberries at 10?°C. These results suggest that LAE/LDPE films are potential candidates for advanced packaging materials for the fruits packaging application.     

油莎豆油的高温煎炸稳定性

以油莎豆油为研究对象,以大豆油为对照,选择过氧化值、p-茴香胺值、共轭二烯含量、共轭三烯含量为评价指标,考察高温煎炸条件下油莎豆油的稳定性,同时通过傅里叶变换红外光谱表征高温煎炸后油莎豆油结构的变化。结果表明：通过比较煎炸次数与过氧化值的关系,油莎豆油的煎炸稳定性略优于大豆油;两种油脂的p-茴香胺值均随煎炸次数增加而增大,大豆油的p-茴香胺值高于油莎豆油,大豆油与油莎豆油的p-茴香胺值与煎炸次数呈明显的相关性,相关系数分别为0982 8和0.988 2;随煎炸次数增加,大豆油中共轭二烯、共轭三烯含量均高于油莎豆油,因此油莎豆油的煎炸稳定性高于大豆油。红外光谱结果表明高温煎炸破坏了两种油脂的不饱和脂肪酸结构。     

Development and Characterization of Soy Protein Isolate Emulsion-Based Edible Films with Added Coconut Oil for Olive Oil Packaging: Barrier,Mechanical, and Thermal Properties

Emulsion-based edible films made of soy protein isolate (SPI), virgin coconut oil (VCO), and soy lecithin (SL) and plasticized with glycerol were prepared using the casting method. The effect of VCO and SL concentrations in SPI films and their in-between interaction were studied through the evaluation of physical (moisture and opacity), mechanical (elongation and tensile strength), water vapor permeability, and thermal properties. The response surface methodology was used to identify the most significant factors in the properties studied. The applicability of SPI emulsion-based films was evaluated as a package for olive oil to be used in small portions. The oxidative stability of the packaged olive oil was monitored by peroxide analyses during 28 days. The incorporation of VCO and SL decreased the moisture content and increased the elongation of the SPI emulsion-based films when compared to the SPI film without these components (control). The opacity of the films increased with the addition of VCO into the protein-based films, but not with the addition of SL or a combination of both constituents. By the other hand, the water vapor permeability was not improved by the incorporation of VCO, SL, or a combination of both. The peroxide value of the olive oil stored in SPI emulsion-based film sachets increased rapidly during the seven first days of storage. After this period, the peroxides increased relatively slow up to 28 days of storage. The peroxide values of the packaged olive oil did not reach the maximum limit recommended by the Codex Alimentarius. Based on these results, this work may be useful for the technological enhancement of emulsion-based films or for food packaging applications.     

Lipid oxidation-related characteristics of gim bugak (Korean fried cuisine with <Emphasis Type="Italic">Porphyra</Emphasis>) affected by frying oil

The effect of frying oil on the lipid oxidation, antioxidants, and in vitro antioxidant activity of gim bugak was studied. Bugak was prepared by pan-frying at 180 °C in unroasted sesame, soybean, extra virgin olive, or palm oil. The degree of lipid oxidation based on conjugated dienoic acid and p-anisidine values was higher in the bugak fried in soybean or sesame oil with high contents of polyunsaturated fatty acids and tocopherols. However, the oil oxidation was lower in olive and palm oils, which showed higher degradation of tocopherols and polyphenols than in sesame or soybean oil during frying. Although the bugak fried in palm oil contained less antioxidants than that fried in soybean or sesame oil, the in vitro antioxidant activity was not different (p > 0.05). Results suggest that palm oil can replace unroasted sesame oil for the preparation of gim bugak with improved lipid oxidative stability and health functionality.     

Modified Atmosphere Packaging of Fresh, "Ready-to-use" Grated Carrots in Polymeric Films

“Ready-to-use” grated carrots were packaged in different films (oxygen permeability from 950 to 22,000 cc/m²/day/atm at 25°C) and stored at 2, 6 or 10°C for 10 days. Gaseous atmosphere in packs and the following were monitored: lactic acid bacteria, yeast counts, exudate and potassium ion released, sugars, carotene, ethanol and lactic acid. The respiration rate of the packaged carrots was measured. Films with very low oxygen permeability resulted in anaerobic respiration, high leakage of potassium, and high lactic acid bacteria. With high-permeability films (between 10,000 and 20,000 cc/m²/day/atm at 25°C), grated carrots showed aerobic respiration and retained good quality. At 10°C, in carrots packed in the most permeable film, sucrose decreased markedly during storage. The gas permeabilities required for packaging grated carrots were evaluated in relation to storage temperature.     

Effect of Chitosan Film Coating Combined with Orange Peel Essential Oil on the Shelf Life of Deepwater Pink Shrimp

In this study, effect of chitosan films combined with orange (Citrus sinensis (L.) Osbeck) peel essential oil on the shelf life of deepwater pink shrimp (Parapenaeus longirostris Lucas 1846) was aimed. Chitosan (CH) and 2% orange peel essential oil (OPEO) combinated chitosan (CH+OPEO) were used for preparing film forming solution. Thickness and microstructure of the films, nutritional composition, sensory and melanosis evaluation, chemical, physical, and microbiological analyses were performed periodically and shelf-life was performed during the storage period of 15 days. The combination of chitosan film with OPEO was effective in prolonging the shelf life of fresh shrimps to 15 days (CH+OPEO), whereas the only chitosan-coated group had a shelf life of 10 days (CH) and the samples packaged without chitosan film had a shelf life of 7 days (control). The results of the study suggested that edible chitosan coatings together with OPEO preserved the shrimps and maintained the shelf life throughout the refrigerated storage period.     

大豆油食用期氧化稳定性的研究

以过氧化值、酸值和p-茴香胺值为评价指标,模拟大豆油家庭食用条件,研究充氮气、添加抗氧化剂(TBHQ)的大豆油(2.5L/桶)在3个月(6、7、8月)食用期内的品质变化规律.结果表明:在3个月的食用期内,2种处理方式下大豆油的过氧化值、酸值和p-茴香胺值均随着时间的延长逐渐增加,其中,过氧化值分别在第70、50 d达到质量安全值5.0 mmol/kg,酸值均小于质量安全值0.2 mg KOH/g,p-茴香胺值变化不大.与添加抗氧化剂相比,氮气储藏同样提高了大豆油的稳定性,氮气储藏可以成为大豆油的一种绿色储藏方法.