Quality of mango fruits during storage: effect of synthetic and eco‐friendly films

Mango (Mangifera indica) cv ‘Alphonso’ fruits, harvested 40–50 days after flowering, were stored at 27 ± 1 °C and 65% RH under three conditions of packaging: (1) perforated plastic boxes, (2) wax lined cartons sealed with low‐density polyethylene (LDPE) film, and (3) wax lined cartons sealed with chitosan films. The weight loss, firmness, Hunter colour values and acidity were determined periodically during storage. Sensory analysis was carried out to determine colour, firmness, flavour qualities and also defective spots. Principal component analysis (PCA) of the results indicated that fruits stored in perforated plastic boxes and LDPE film‐sealed cartons differed significantly with respect to mango flavour, firmness and development of defective spots, while those in chitosan film sealed cartons retained the desirable qualities for a longer period (up to 20 days) without developing defective spots. The higher level of carbon dioxide and lower level of oxygen, or lower rate of oxygen transmission, associated with chitosan films delay ripening, and the higher water vapour transmission rate minimizes the rate of transpiration and prevents condensation of water droplets on the film. This helps in establishing equilibrium moisture content of mangoes in the cartons, which, in turn, extends the shelf life of fruits for a longer period. Copyright © 2004 Society of Chemical Industry     

A comparative study on the effect of packaging material and storage environment on shelf life of fresh bell-pepper

The effect of packaging materials [low density polyethylene (LDPE), polypropylene (PP)] and storage environment [modified atmospheric packaging (MAP)] on shelf life enhancement of bell pepper in terms of quality attributes such as physiological weight loss, ascorbic acid, texture, surface colour and subjective quality analysis have been studied at ambient and refrigerated condition. Different packaging techniques used for the experiment were MAP with LDPE, MAP with PP, MAP in perforated LDPE films, MAP in perforated PP films, shrink packaging with bi-axially oriented PP (BOPP) film and vacuum packaging with PP film. The in-pack bell pepper created a suitable headspace environment with low O₂ and high CO₂ concentrations, which resulted in a better retention of freshness of the vegetables and its marketability. Shrink packaging with BOPP film could not yield better result under ambient storage because of high water vapor transmission rate of the film and consequently loss of turgidity of the vegetables. Among different packaging techniques and storage conditions, MAP with PP film in refrigerated condition was found to be the best followed by vacuum pack with PP film in refrigerated condition and could be used to store for 20 days for bell pepper with maintenance of texture, colour, ascorbic acid and marketability. It is also inferred that under ambient conditions, bell pepper could be stored for 4 days using ventilated LDPE and PP as MAP storage. Further studies are needed to evaluate the sensory aspects, as well as to microbiological evaluation to characterize the fresh bell pepper during storage.     

Effect of irradiation, active and modified atmosphere packaging, container oxygen barrier and storage conditions on the physicochemical and sensory properties of raw unpeeled almond kernels (Prunus dulcis)

BACKGROUND: The present study investigated the effect of irradiation, active and modified atmosphere packaging, and storage conditions on quality retention of raw, whole, unpeeled almonds. Almond kernels were packaged in barrier and high‐barrier pouches, under N₂ or with an O₂ absorber and stored either under fluorescent lighting or in the dark at 20 °C for 12 months. Quality parameters monitored were peroxide value, hexanal content, colour, fatty acid composition and volatile compounds. Of the sensory attributes colour, texture, odour and taste were evaluated. RESULTS: Peroxide value and hexanal increased with dose of irradiation and storage time. Irradiation resulted in a decrease of polyunsaturated and monounsaturated fatty acids during storage with a parallel increase of saturated fatty acids. Volatile compounds were not affected by irradiation but increased with storage time indicating enhanced lipid oxidation. Colour parameters of samples remained unaffected immediately after irradiation. For samples packaged under a N₂, atmosphere L* and b* values decreased during storage with a parallel increase of value a* resulting to gradual product darkening especially in irradiated samples. CONCLUSION: Non‐irradiated almonds retained acceptable quality for ca. 12 months stored at 20 °C with the O₂ absorber irrespective of lighting conditions and packaging material oxygen barrier. The respective shelf life for samples irradiated at 1.0 kGy was 12 months packaged in PET‐SiOx//LDPE irrespective of lighting conditions and 12 months for samples irradiated at 3 kGy packaged in PET‐SiOx//LDPE stored in the dark. Copyright © 2010 Society of Chemical Industry     

Effects of packaging materials following ethanol and benomyl treatments on chemical and microbiological changes in tomato (Lycopersicon esculentum) fruits

The effects of various post-harvest treatments on chemical changes, microbiological quality and occurrence of spoilage in ripe tomatoes (Lycopersicon esculentum L) were investigated. Fruits were pretreated in 70% ethanol or 0.2% benomyl before being packaged in low density polyethylene (LDPE), high density polyethylene (HDPE) or raffia palm basket. Fruit was stored at 27–32°C for up to 16 days. Control fruits (without pretreatment or packaging) showed the highest increase in pH; basket-packaged fruits were erratic but LDPE- and HDPE-packaged fruits showed gradual increases. Changes in titratable acidity were the inverse of those in pH. Among packagings, LDPE most effectively maintained total soluble solids (TSS) as compared with basket-packaged fruits, and the control showed the lowest TSS. Of the pretreatments, benomyl-treated fruits retained higher TSS. Aspergillus spp, Penicillium spp, Pseudomonas spp and Escherichia spp occurred most commonly in control and basket-packaged fruits, but Rhizopus spp and Leuconostoc spp predominantly occurred in LDPE- and HDPE-packaged fruits. Microbial load was lowest in benomyl-treated fruits followed by ethanol-treated and control fruits. Spoilage was higher (53.1%) in ethanol-treated than in benomyl-treated (43.8%) fruits.     

Effects of Modified Atmosphere Packaging on the Physicochemical Characteristics of Ciku ( Achras sapotaL) at Various Storage Temperatures

The physicochemical changes in ciku during storage at various temperatures and the effect of various techniques of modified atmosphere packaging (MAP) at 5, 10, 15°C and ambient were examined by monitoring fruit texture, weight loss, soluble solids content, pH, sucrose, fructose, glucose, pectin, tannin, ascorbic acid and microbial infection. Under MAP, ciku could be stored for 4 weeks at 10°C and 3 weeks at 15°C, while without MAP the storage life was shorter by 1 week. Packaging in low-density polyethylene film (LDPE) was highly effective in maintaining the texture and weight of cold-stored fruits. Fruits stored at 5°C experienced chilling injury, observed as their inability to ripen properly, even after 3 days at room temperature in the presence of 50 g kg⁻¹ calcium carbide. The ascorbic acid content was highest in vacuum-packed fruits followed by the other LDPE packagings. LDPE packaged fruits also received the highest sensory scores for taste, colour, texture and overall acceptability in cold-stored ciku. The unsealed nature and heating involved in shrink wrapping did not favourably affect the storage life of ciku. MAP alleviated the chilling injury which occurred in ciku stored at 10°C but not at 5°C.     

Drying characteristics and product quality of bell pepper

Drying characteristics and quality attributes of bell pepper strips were studied at selected pre‐treatments and drying air temperatures. Blanching of strips in solution (1% sodium hydroxide and 0.25% magnesium carbonate) retained maximum amount of chlorophyll in the product. Constant rate and the falling rate period were observed when bell pepper dried in air convection at 50 and 60°C. However, the constant rate period was not observed when dried at 70°C. Page's model described adequately the drying behavior of bell pepper under the falling rate period. Sensory quality attributes, chlorophyll content, bulk density and rehydration capacity were found to be most acceptable when the pre‐treated strips were dried at 50°C.     

Nutritional improvement of bhujia by incorporating colored bell peppers

The present study aimed at improving phytonutritional profile of traditional snack (bhujia) by incorporating variety bell pepper. The bell peppers were dried at 50°C which resulted in 4.94%–8.16% increase in total phenols whereas, retained approximately 92.49% total carotenoids and 91.36% of the antioxidant activity in terms of DPPH radical scavenging activity. Gram flour at 5.0% (w/w) level of bell pepper powders was optimized for developing bhujia which significantly (p ≤ 0.05) increased bulk density, minerals, phytonutritional profile, and sensory attributes of bhujia. Total phenols of developed bhujia increased by approximately 11% and antioxidant activity was found 3.5 times as compared to control. Fourier-transform infrared spectroscopy showed the presence of various phytochemicals compounds in the prepared products compared to control. Storage studies (at 25–30°C/50%–87% RH) revealed that the physicochemical parameters remained unaffected except moisture which increased significantly. However, peroxide value and free fatty acids remained well within maximum permissible limits.     

Characterisation of antioxidant compounds in sweet bell pepper (Capsicum annuum L.) under organic and conventional growing systems

BACKGROUND: Sweet red bell pepper is one of the best sources of ascorbic acid and carotenoids as well as phenolic compounds important in the human diet. There have been some studies showing a higher level of bioactive compounds in organic bell pepper fruits compared with conventional fruits, but not all studies have been consistent in this respect. The levels of carotenoids and phenolics are very variable and may be affected by ripeness, genotype and cultivation. RESULTS: The results obtained in this study showed that an organic growing system affected the level of bioactive compounds (carotenoids and polyphenols) in sweet bell pepper fruits cultivated in Poland. Organic bell pepper fruits contained significantly more dry matter, vitamin C, total carotenoids, β‐carotene, α‐carotene, cis‐β‐carotene, total phenolic acids (as well as individual gallic and chlorogenic acids) and flavonoids (quercetin D ‐glucoside, quercetin and kaempferol) compared with conventional fruits. The bell pepper variety also affected the level of antioxidant compounds in fruits. CONCLUSION: Organic growing increased the level of antioxidant compounds such as carotenoids, phenolic compounds and vitamin C in sweet bell pepper. The second significant factor affecting the antioxidant compound content of sweet bell pepper was variety. It would be necessary to continue this study as a long‐term experiment in order to eliminate the influence of seasonality. Copyright © 2012 Society of Chemical Industry     

Absorption of Aroma Volatiles of Orange Juice into Laminated Carton Packages Did Not Affect Sensory Quality

Orange juice was stored in glass bottles and polyethylene/barrier material laminated cartons at 4°C for 24 wk. Studies were carried out on the absorption of 19 orange juice aroma compounds (e.g ethyl butyr-ate, d-limonene) into low density polyethylene (LDPE). Sensory evaluations were performed on the same orange juice in different packages over the storage period. A reduction of d-limonene of up to 50% by absorption into the LDPE inside coating was observed. However, an experienced sensory panel did not distinguish between orange juice stored in glass bottles and polyethylene laminated cartons.     

The microbial safety of strawberry and raspberry fruits packaged in high-oxygen and equilibrium-modified atmospheres compared to air storage

Microbial safety of strawberry and raspberry fruits was assessed after shelf‐life extension by two new packaging systems, high‐oxygen atmospheres (HOA) and equilibrium‐modified atmospheres (EMA), in combination with an ethylene absorbing film. Both fruits had a shelf‐life of 3 days at 7 °C when macroperforated films were used. Strawberry fruits were acceptable for 5 days in both packages, raspberries had a shelf‐life of 7 and 5 days when using EMA and HOA respectively. Escherichia coli, Salmonella spp. and Listeria monocytogenes were artificially inoculated onto packaged fruits. All were able to survive on packaged fruits stored at 7 °C. Raspberries showed an enhanced inactivation of Salmonella during storage time in both types of packaging. Growth of L. monocytogenes was observed on the calyx of strawberries after the end of the established shelf‐life. Generally, increasing the shelf‐life of the fruits with EMA and HOA did not give an increased microbial risk.     

Sensory Characteristics of Fresh-Cut Spinach Preserved by Combined Factors Methodology

Fresh‐cut spinach was treated with citric acid and ascorbic acid solutions and packaged in monooriented polypropylene (OPP) bags or low density polyethylene (LDPE) bags. Sensory attributes, chlorophyll retention, and weight loss were evaluated throughout refrigerated storage. Mathematical models were developed to analyze and predict the effect of the citric acid and ascorbic acid concentrations and storage time on off‐odor development, general appearance, wilting, browning, and color. Sensory attributes of fresh‐cut spinach decreased with storage time. Type of film affected off‐odor development, but did not influence visual sensory attributes. Chemical treatment and type of packaging film did not affect chlorophyll retention. Both types of packaging film controlled weight loss.     

Effects of Retail Style or Food Service Style Packaging Type and Storage Time on Sensory Characteristics of Bacon Manufactured from Commercially Sourced Pork Bellies

Objectives were to characterize differences in pork bellies that were stored frozen for different durations prior to processing and characterize sensory properties of the bacon derived from those bellies when stored in either retail or food service style packaging. Bellies (n = 102) were collected from 4 different time periods, fresh bellies (never frozen) and bellies frozen for 2, 5, or 7 mo, and manufactured into bacon under commercial conditions. Food service bacon was packaged in oxygen‐permeable polyvinyl lined boxes layered on wax‐covered lined paper and blast frozen (–33 °C) for 45 or 90 d after slicing. Retail bacon was vacuum‐packaged in retail packages and refrigerated (2 °C) in the dark for 60 or 120 d after slicing. At the end of respective storage times after slicing, bacon was analyzed for sensory attributes and lipid oxidation. Off‐flavor and oxidized odor of bacon increased (P < 0.01) with increasing storage time in both packaging types. Lipid oxidation increased (P < 0.01) as storage time increased from day 0 to day 45 in food service packaged bacon from frozen bellies, but was unchanged (P ≥ 0.07) with time in food service packaged bacon from fresh bellies. Lipid oxidation was also unchanged (P ≥ 0.21) over time in retail packaged bacon, with the exception of bellies frozen for 5 mo, which was increased from day 0 to day 90. Overall, off‐flavor, oxidized odor, and lipid oxidation increased as storage time after processing increased. Freezing bellies before processing may exacerbate lipid oxidation as storage time after processing was extended.     

Aroma Changes in Fresh Bell Peppers (Capsicum annuum) after Hot-air Drying

The aroma of fresh and hot-air dried bell peppers (Capsicum annuum) was evaluated by sensory and instrumental methods. Hot-air drying decreased levels of the odor compounds (Z)-3-hexenal, 2-heptanone, (Z)-2-hexenal, (E)-2-hexenal, hexanol, (Z)-3-hexanol, (E)-2-hexenol, and linalool, which have green, vegetable-like, fruity, and floral notes, while intensity scores of corresponding sensory aroma attributes also decreased. The aroma of rehydrated dried samples was mainly characterized as savory, rancid/sweaty, sweet/sickly, hay-like, cacao, caramel, and nutty. Drying increased the levels of 2-methylpropanal, 2-and 3-methylbutanal, which have cacao, spicy, and rancid/sweaty odor notes; these volatiles may be correlated with the corresponding aroma attributes in the dried fruits. Principal component analysis demonstrated relationships between instrumental and sensory data for fresh samples, whereas they were more complex for dried fruits.     

正交试验优化魔芋葡甘聚糖复合膜配方及其对青椒的保鲜作用

以魔芋葡甘聚糖为膜基质,利用5因素2水平正交试验筛选对青椒具有良好保鲜作用的涂膜保鲜剂组合,分析其对青椒的衰老指数、丙二醛(MDA)含量、VC含量和叶绿素含量的影响。结果表明：青椒的最佳复合涂膜剂组合为8.0g/L魔芋精粉+1.0g/L曲酸+0.4g/L EDTA+0.1g/L抗坏血酸+0.35%甘油。该涂膜组合处理青椒,贮藏30d后,衰老指数为0.32,MDA、VC含量和叶绿素含量分别为0.87nmol/g、25.0mg/100g和0.08mg/g,保鲜效果明显优于对照。     

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.     

Employing an intelligence model and sensitivity analysis to investigate some physicochemical properties of coated bell pepper during storage

The objectives of this work were to study the effects of three different coatings (gum Tragacanth, sesame oil and gum Tragacanth–sesame oil), temperature and time on shelf life of bell pepper. Moisture reduction, shrinkage as well as firmness and colour changes were studied during 30 days at 4, 10, 15 and 23 °C. Results of this study showed that bell peppers treated with gum Tragacanth at higher temperatures, such as 10 °C, had good quality up to 30 days of storage. However, sharp changes in physicochemical characters were observed in bell peppers stored at 23 °C. In order to predict moisture reduction, shrinkage, firmness and colour changes genetic algorithm–artificial neural network model was developed. It was found that artificial neural network with eight hidden neurons truly could predict the physicochemical changes of bell pepper during storage (R² > 0.9598). The results of sensitivity analysis showed that shrinkage percentage and also changes of firmness and colour were very sensitive to storage time, while storage temperature had the most effect on moisture reduction.     

QUALITY OF MINIMALLY PROCESSED LETTUCE AS INFLUENCED BY PACKAGING AND CHEMICAL TREATMENT

Shredded lettuce was packaged in sealed bags of monooriented polypropylene (OPP) film and also in polyethylene (PE) trays overwrapped with a multilayer polyolefin (RD106) or plasticized polyvinyl chloride (PVC) film; and stored at 4C in a refrigerated case during 8 days. Chemical treatment by dipping in a 0.3% ascorbic acid /0.3% citric acid solution did not significantly affect changes in microbial populations or visual sensory attributes. Type of package was not a significant factor for microorganism populations, but was significant (p<0.001) for changes in gas composition and visual sensory attributes. The modified atmosphere within the packages changed from normal air composition to about 1.5% O₂/12% CO₂ for OPP bags and to about 17–18% O₂/1–2% CO₂ for PVC-PE trays and RD106-PE trays after 8 days of storage. The visual sensory quality of the product was retained better in OPP bags than in the other ones.     

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     

Stabilisation of colour and odour of beef patties by using lycopene‐rich tomato and peppers as a source of antioxidants

Beef patties containing natural antioxidants—cayenne hot pepper, red sweet pepper, lycopene‐rich tomato pulp (LRTP) and extract of tomato rich in lycopene (Lyc‐O‐Mato?)—and packaged in modified atmosphere were evaluated for storage stability at 2 ± 1 °C by measuring CIE a* values, surface metmyoglobin, TBARS, psychrotrophic bacteria counts and sensory off‐odour and discolouration. Results demonstrated that the addition of ground peppers (both sweet and hot) to beef patties delayed and inhibited very significantly (p < 0.05) the oxidation of both myoglobin and lipid as well as the growth of psychrotrophic bacteria. As a consequence, and according to instrumental and sensory results of meat colour and odour, the shelf life of beef patties was extended from about 4 to about 16 days. Capsaicinoid‐rich cayenne hot pepper exerted a more intense antioxidative effect than capsaicinoid‐free red sweet pepper. The addition of lycopene‐enriched tomato products (LOM and LRTP) was not as effective as treatment with peppers, although they exerted a significant (p < 0.05) antioxidative effect too, depending on the lycopene concentration. These tomato products delayed meat deterioration to a varying extent, so that the shelf life of treated beef patties ranged between 8 and 12 days. © 2003 Society of Chemical Industry