Polyethylene Trays Research Articles

Germination behavior of Jatropha curcas L. after different imbibition times

Jatropha curcas is an important specie for production of biofuel. The specie can survive and produce fruits and seeds even in drought condition. For an adequate establishment in the field is necessary that seeds have a good quality in vigor and viability. In this study, we evaluated the seed water relation with different imbibition times, in deionized water, from 0 to 24 hours. Imbibed seeds were sown in polyethylene trays with 1,200 g of river sand. The germination was recorded every day for 25 days. Seeds with at least 10 mm radicle on the soil surface was considered as germinated. To determinate seed water content (SWC), 10 seeds were weighed in fresh (SFW), turgid (STW) and dry weight (SDW) at 105°C for 24 hours. After 24 hours of imbibition our results show a decrease in the germination rate from 85% to 47%, and an increase of the mean germination time from 4.8 to 7.1 days. The initial moisture of the seed used in this experiment was about 8% and after 24 hours of imbibition, the SWC was around 60%. The initial low moisture in the seeds produce imbibition damage because the tissue hydration takes place in a not controlled way so that the reconstruction of internal structures of the cells and organelles were affected. According to the PCA analysis the seed germination had a negative correlation with the imbibition time (r = -0.72, p < 0.05) and with the electrical conductive (r = -0.88, p < 0.05), variables related to the seed vigor. This study suggests that electrical conductivity may be useful in J. curcas for vigor test and their seeds do not need previously water imbibition to improve germination from seeds with initial moisture less than 8%.

Combined effects of natural additives and modified atmosphere on quality of fresh cut peaches

The aim of this study was to evaluate the combined use of natural additives and modified atmosphere on the physicochemical and microbiological characteristics of fresh cut peaches 'El Dorado'. The minimal processing consisted of washing, peel and sanitization. The slices were immersed into the following treatment solutions: distilled water control (T1, control); 2% CaCl 2 (T2); 2% ascorbic acid (T3); 2% citric acid (T4); 1% CaCl 2 + 1% ascorbic acid + 1% citric acid (T5); 2% CaCl 2 + 2% ascorbic acid + 2% citric acid (T6). Peaches slices were placed on polyethylene trays, covered by a polyethylene film with modified atmosphere of 2 % O 2 , 5% CO 2 and 93 % N 2 , and kept in cold storage at 5 °C ± 2 °C for nine days. On days 0, 5, 7 and 9, the following variables were analyzed: total soluble solids, total titratable acidity, pH, total sugar, firmness, counts of mesophiles, heat-tolerant coliforms (45 o C), yeast and mold counting and sensory analysis of the attributes appearance, color, flavor, texture and overall acceptability. The T5 treatment combined with the use of modified atmosphere demonstrated best qualitative and microbiological characteristics for fresh cut peaches during nine days of storage.

GENETIC DIVERSITY AMONG Calotropis procera (Aiton) WT Aiton GENOTYPES ACCORDING TO SEED PHYSIOLOGICAL QUALITY

ABSTRACT Characterizing genetic diversity based on evaluations involving germination and seed vigor, is a fundamental stage in starting the development of a cultivation system for Calotropis procera. Thus, this study aimed to estimate genetic diversity among 35 C. procera genotypes based on germination and vigor of seeds stored for 1 year. The genotypes, which originated from areas in Paraíba (Brazil), where they occur naturally, were collected and stored in March 2014. In order to evaluate the physiological potential of the seeds, two experiments were conducted between March and April 2015. The first involved a propagation test conducted in a germination chamber, while the second involved an emergence test in washed sand, performed in polyethylene trays in a screened environment under uncontrolled conditions. In both experiments, an entirely randomized design was used, with four repetitions of 25 seeds per genotype. The characteristics evaluated were germination, average daily germination, daily germination speed, the speed of germination index, the plantlet vigor index, emergence, the speed of emergence index, total length, and total dry mass. The results showed that genetic variability exists among the C. procera genotypes for variables involving germination and vigor of seeds stored for 1 year. Also, emergence, total dry plantlet mass, and germination characteristics contribute most to the genetic divergence among C. procera genotypes.

Nitrite Embedded Vacuum Packaging Improves Retail Color and Oxidative Stability of Bison Steaks and Patties

Bison meat is prone to rapid discoloration under traditional aerobic retail packaging conditions. The aim of this study was to determine if the color stability of bison steaks and burger patties could be improved through packaging meat with a vacuum-sealed film containing embedded sodium nitrite. Bison bulls (n = 40) were slaughtered and the longissimus lumborum (LL) and rhomboideus (RH) were removed. Following a postmortem aging period of 6, 13, or 20 d steaks were obtained from the LL. RH muscles aged 6 d were ground (85:15 lean to fat) and formed into 140 g patties. One steak and two burger patties from each carcass side were placed into either a polystyrene tray overwrapped with oxygen permeable polyvinyl chloride film (CONT) or a polyethylene tray vacuum sealed with film coated in sodium nitrite (113 mg × m–2; NIT); meat was placed under simulated retail conditions for 4 d. A 3-way interaction was observed between packaging type, whole muscle aging and time in retail display for objective (L*, Chroma, and Hue) and subjective (lean color score and proportion of surface discoloration) color measures from steaks (P &lt; 0.0001). The CONT packaged meat showed an increased area of discoloration and in metmyoglobin after 4 d in retail display (P &lt; 0.0001); NIT meats did not show a higher area of discoloration or metmyoglobin after retail display. Additionally, NIT packaged steaks and burger patties lightened (higher L*) and became redder over the course of the retail display period. Thiobarbituric acid reactive substances (products of lipid peroxidation) did not increase in NIT packaged burger patties after 4 d under retail conditions, however, there was a significant increase observed for CONT packaged burger patties (P &lt; 0.0001). NIT packaging appears to effectively improve the color stability of bison meat under retail conditions, making this packaging strategy well suited to address the issue of rapid discoloration.

Effect of Chemical Treatments on the Quality of Fresh-Cut Globe Artichoke (Cynara scolymus,L.) During Cold Storage

Fresh-cut heads of globe artichoke cultivar French Hyrious were dipped in solutions of Gibberellic acid (GA3) at 100, 200 and 300 ppm, Potassium sorbate (PS) at 1, 2 and 3% and edible coating Chitosan at 1, 2, and 3 % for 5 minutes then placed in polyethylene trays that covered with polypropylene film which closed thermally and stored at 0oC and 95% R.H. GA3 exhibited comparatively the most obvious results during storage in lessening the deterioration of loss in weight, unmarketable percentage, T.S.S, inulin beside lowering the activity of polyphenol oxidase enzyme. The maximum T.S.S % was obtained from gibberellic acid at 200 ppm, potassium sorbate 1% and chitosan 3%. The application of gibberellic acid led to keep the highest total sugars content at 200 ppm followed by potassium sorbate at 1% and finally chitosan at 2%. The maximum inulin content happened due to the application of gibberellic acid at 200 ppm followed by potassium sorbate 3% and at least was chitosan at 3%. The highest ascorbic acid was obtained from the application of GA3 at 200 ppm, 3% potassium sorbate and 2% chitosan respectively. Gibberellic acid at 200 ppm followed by potassium sorbate 1 % exhibited the least enzyme activity while chitosan at 1 %reflected the highest activity during the various storage periods.

Quality improvement and shelf life extension of fresh apricot fruit (Prunus Armeniaca cv. Shahroudi) using postharvest chemical treatments and packaging during cold storage

The main objective of this work was to assess the effectiveness of salicylic acid (SA), calcium chloride (CaCl2) or sodium bicarbonate (NaHCO3), and packaging on some qualitative properties of apricot fruit during cold storage. The experiments were conducted using a completely randomized design as factorial, with three replicates. Fruits were dipped in SA (0.1 or 0.5 mM), CaCl2 (1 or 2%) or NaHCO3 (0.2 or 0.5%) solutions for 3 min at 22°C. Then, fruits were placed into polyethylene trays and wrapped with cellophane films to create a passive modified atmosphere packaging, whilst the second group remained unwrapped. Fruits were stored in a cool room at 0.5 ± 0.5°C. Regardless of chemical treatments, total soluble solids (TSS), organoleptic characteristics, and shelf life were higher in packed fruit compare to unpacked fruit. The TSS, weight loss and firmness were lower in fruits covered with cellophane compared to unwrapped fruit. Fruits that treated with SA (0.5 mM) and covered with cellophane film had the lowest TSS while treated fruit with CaCl2 (1%) with no cover indicated the highest TSS. Generally, there was a significant decrease in fruit firmness under the cellophane layer compare to unpacked fruits while in treated fruit with CaCl2 (1%) firmness in packed fruit was obviously higher than unpacked fruits. The best visual quality and taste were obtained in treated fruit with CaCl2 (2%), followed by SA (0.5 mM) when they were packed with cellophane film. The highest shelf life obtained in treated fruit with SA (0.1 mM), followed by NaHCO3 (0.5%). Overall, a combination of chemical treatments and packaging with cellophane film improved fruit quality and extend shelf life significantly compared to the control.

Bioassays for comparative infectivity of mermithid nematodes (Romanomermis iyengari, Romanomermis culicivorax and Strelkovimermis spiculatus) for culicine mosquito larvae

Two improved bioassays were developed to establish infectivity baselines for selection experiments using mermithid nematode variants. Comparative infectivity of Romanomermis iyengari, Romanomermis culicivorax and Strelkovimermis spiculatus using larvae of three mosquito spp. Aedes sierrensis, Aedes aegypti and Culex pipiens were evaluated with “plate” and “tray” bioassays at selected intensity of infections. Using the “plate” bioassay, single mosquito larvae were immersed in 2ml of water within individual depressions of 12-well, polystyrene tissue culture plates. One, three, or five preparasitic juveniles (J2) were added to each well. In the “tray” bioassay, polyethylene trays containing 500ml water and 100 mosquito larvae were exposed to 500 (5:1, nematode:insect host) or 1000 (10:1) J2s. Percentage infection (PINF, infectivity) and intensity of infection (IINF, #nematodes per infected larvae) number were determined only after emergence of post-parasitic J3 juveniles. Under the bioassay conditions, all three species of nematodes resulted in infections in all mosquito hosts, but R. iyengari exhibited better effectiveness in the parasitism of mosquito larvae. The three species of mosquitoes presented high levels of susceptibility to each of the three species of nematodes, but in general Cx. pipiens and Ae. sierrensis were slightly more susceptible than Ae. aegypti. The “plate” bioassay was more efficient in measurement of infectivity of the mermithid species and in establishing baseline characteristics for these mosquito-parasitic nematodes. The “tray” bioassay was an effective bioassay for large cohorts of both infective juveniles and host larvae and, potential for field interactions.

Determination of Optimal Storage Condition for Pre-packed Hanwoo Loin

The aim of this study was to determine the optimal storage condition of pre-packed Hanwoo beef without freezing. Hanwoo loin was purchased from a local distributor at 48 h after slaughter, then sliced in 1.5±0.5 cm thickness, and packed in a polyethylene (PE) tray covered with linear low-density polyethylene (LLDPE) film. The studied factors to set the optimal storage condition were chamber temperature (5, 2.5 and -1 o C for 14 d), cooling method (direct and indirect cooling system), and ultraviolet (UV) light irradiation for beef surface sterilization (0, 30, 60, and 120 min). The changes of pH, thiobarbituric acid reactive substances (TBARS) and number of aerobic bacteria were measured during storage. Beef samples stored in -1 o C showed the minimal increasing rate in TBARS and microbial growth. After 15 d of storage, there was no significant difference in pH and TBARS values. However, the microbial population of beef stored in direct type cooling chamber (4.25±0.66 Log CFU/g) was significantly lower than that of beef stored in indirect type chamber (6.47±0.08 Log CFU/g) (p<0.05). After 4 d of storage, 60 or 120 min UV light irradiated beef samples showed significantly lower microbial population, and at 14 d of storage, 60 min UV irradiated beef sample showed significantly lower microbial population (3.14±0.43 Log CFU/g) than control (4.46±0.13 Log CFU/g) (p<0.05). However, TBARS values of 60 or 120 min UV light irradiated beef samples were significantly higher than non-irradiated beef sample after 4 d of storage (p<0.05).

Brotação e produção de mandioquinha-salsa 'Amarela de Carandaí', proveniente de mudas desinfectadas com óleo de eucalipto e enraizadas em bandejas

Objetivou-se avaliar a brotação das mudas e a produção de mandioquinha-salsa 'Amarela de Carandaí', provenientes de mudas desinfectadas com óleo de eucalipto e enraizadas em bandejas de isopor. No pré-enraizamento em bandejas, utilizou-se a matriz experimental Plan Puebla III para combinar concentrações de óleo de eucalipto e tempos de imersão, respectivamente: 0,6%/36 s; 1,4%/36 s; 0,6%/84 s; 1,4%/84 s; 1,0%/60 s; 0,1%/36 s; 1,9%/84 s; 0,6%/6 s e 1,4%/114 s, mais uma testemunha (0,0%/0 s). No campo, utilizaram-se 10 mudas por parcela e seis tratamentos: 0,6% s; 36 s; 0,6%/84 s; 1,0%/60 s; 0,1%/36 s; 0,6%/6 s e 0,0%/0 s. Maiores porcentagens de mudas brotadas e altura de plantas foram obtidas nos tratamentos onde se utilizaram concentrações de óleo de eucalipto menores que 1,0% e na testemunha. As maiores massas frescas de raízes comerciais, nas colheitas aos 264 dias após o plantio, foram obtidas nos tratamentos 0,6%/36 s, 0,6%/84 s e 1,0%/60 s. Houve queima das folhas provocadas por Alternaria sp e Septoria sp., com maior intensidade aos 111 dias após o plantio, associadas e sem possibilidade de quantificação isoladamente. Concluiu-se que, para se obter maior produção de raízes comerciais, as mudas devem ser desinfectadas em solução aquosa com doses de 0,6% ou 1,0% de óleo de eucalipto e imersão em tempos de 36 s a 84 s, sendo a colheita aos 264 dias após o plantio.

Germinação e expressão morfológica de frutos, sementes e plântulas de Pilosocereus pachycladus Ritter

It was aimed to present the results on the germination, morphology of fruits, seeds and description of stages of plant growth of Pilosocereus pachycladus. The seeds were obtained from fruits harvested at the Curu Valley Experimental Farm, in Pentecoste - CE. Ten fruits were used to the realization of the biometric and morphological determinations. For description of the morphology of the seeds, were considered the external and internal aspects. Two light conditions (12 hours photoperiod and total darkness) and three temperatures (25; 30 and 20-30 °C) were tested in a factorial arrangement 2 x 3 arranged in a completely randomized design with four replications of 50 seeds each. Counts were done daily until the 16 th da y after sowing and to evaluated: the percentage and velocity index of germination. For description of the morphology of the seeds, were considered the external and internal aspects. For description and illustration of the external morphology of germination and seedling, were sowed 200 seeds in a polyethylene tray. The processes of germination and seedling growth were evaluated during 150 days and eight stages of development were characterized and those were based on morphological differences observed. It was concluded that, the fruit measures 38.13 mm of length, 50.53 mm of thickness and 3786 seeds. The constant temperatures of 25 oC and 30 oC under a photoperiod of 12 hours made possible the highest percentages and velocities of germination and the seeds behave as photoblastic positive. 150 days after sowing, the epicotyl is growing with a large amount of thorns and 94.31 mm of length.

Large-scale Micropropagation of Aloe vera

A protocol for large-scale Aloe vera (L.) Burm. f. production was established using micropropagation of apical buds. The effects of two chlorine-based disinfectants were evaluated on the survival of the explants in different treatments in a semisolidified Murashige and Skoog (MS) medium in the presence of 6-benzylaminopurine (6-BAP; 2 mg·L−1). During 120 days, 136 green apical shoots bearing axillary buds were multiplied four times at 30-day intervals in the same MS medium, reinoculating seven to nine explants per flask each time. The elongation and rooting processes were carried out in the same MS medium without 6-BAP. A total of 40,495 Aloe vera microplants were obtained, a yield of 300 microplants per apical bud at a rate of 1:5.3 in every multiplication period of 30 days. From that total, 38,480 Aloe vera microplants were successfully acclimatized transferring to 36- and 64-cell polyethylene trays containing proper substrate in two different ex vitro greenhouse conditions. After a 3-month period, fresh and dry matter weights of the Aloe vera plants were determined. All the data from each experimental phase were statistically analyzed. The use of 64-cell (40 cm3/cell) trays represented an economy of 47.37% in greenhouse space and 50% in the amount of substrate per Aloe vera plant.

The combined effect of superchilling and modified atmosphere packaging using CO2 emitter on quality during chilled storage of pre‐rigor salmon fillets (Salmo salar)

AbstractBACKGROUND: Pre‐rigor fillets of Atlantic salmon were either superchilled or chilled prior to packaging in air or in modified atmosphere (MAP, 60% CO2/40% N2) with a CO2 emitter, in 5.3 L high‐density polyethylene trays with three to four layers of fillets (3.0–3.7 kg). All samples were stored at 0.1 °C for 28 days.RESULTS: Fillets stored in MAP had significantly lower bacterial growth compared to fillets stored in air, and MAP superchilled bottom fillets had lower bacterial counts compared to the corresponding chilled fillets. Samples superchilled prior to refrigerated storage in air had similar bacterial growth to ordinary chilled samples. Faster fillet softening during storage and higher liquid loss were observed in superchilled MAP samples.CONCLUSION: Combining short‐term superchilling and MAP with a CO2 emitter prolonged the shelf‐life of pre‐rigor salmon fillets, which can improve sustainability throughout the value chain. The superchilling method needs to be optimized to avoid negative effects on texture and liquid loss. Copyright © 2009 Society of Chemical Industry

Influência da idade biológica da planta matriz e do tipo de estaca caulinar de caramboleira na formaçâo de raízes adventicias

Comercialmente, o método mais utilizado na propagação da caramboleira (Averrhoa carambola L.) é a enxertia, que pode ser realizada por borbulhia ou garfagem. Porém, esse método apresenta algumas características que podem tornar a produção de mudas onerosa, exigindo mão-de-obra especializada e maiores custos quando comparado com o método de estaquia. Objetivou-se, neste trabalho, verificar a influência dos tipos de estacas (apical e mediana) e da idade biológica da planta (juvenil e adulta) na capacidade de formação de raízes adventícias em estacas de caramboleira. Estacas herbáceas de caramboleira foram coletadas de ramos de plantas juvenis (1 ano) e adultas (15 anos), padronizadas com um par de folhas inteiras e 12 cm de comprimento. Em seguida foram colocadas em bandejas de poliestireno contendo como substrato vermiculita média, em câmara de nebulização intermitente com 50% de sombreamento. O experimento foi conduzido em delineamento inteiramente casualizado, em arranjo fatorial 2 x 2, onde os fatores estudados foram tipos de estacas (apical e mediana) e idade biológica da planta (juvenil e adulta). Após 70 dias, avaliaram-se as porcentagens de estacas enraizadas, estacas vivas, estacas brotadas e o número de raízes emitidas por estaca. O tipo de estaca não influenciou em nenhuma das variáveis analisadas. Concluiu-se que as estacas juvenis de caramboleira se mostraram mais eficientes na formação de raízes adventícias (47%), quando comparadas com as estacas retiradas de plantas com idade biológica adulta.

Enraizamento de estacas lenhosas e herbáceas de cultivares de caquizeiro com diferentes concentrações de ácido indolbutírico

Desenvolveu-se este trabalho com o objetivo de estudar a capacidade de enraizamento de estacas lenhosas e herbáceas de cultivares de caquizeiro tratadas com AIB. Estacas lenhosas e herbáceas foram coletadas de ramos de caquizeiro das cultivares Pomelo, Rama Forte, Taubaté, Giombo e Fuyu e submetidas à aplicação de AIB (0; 3.000 e 6.000 mg.L-1 por vinte segundos). Em seguida, as estacas foram colocadas em canteiro contendo uma mistura de terra + esterco de curral (3:1 v/v) como substrato (estacas lenhosas) e em bandejas de poliestireno expandido, contendo vermiculita média, em câmara de nebulização intermitente (estacas herbáceas). Como conclusão, observou-se que as cultivares de caquizeiro apresentam diferenças quanto ao potencial de formação de raízes e brotações; estacas herbáceas apresentam maior tendência na propagação via estaquia em comparação às estacas lenhosas.

Influência de embalagens e temperatura no armazenamento de jabuticabas (Myrciaria jabuticaba (Vell) Berg) cv 'SABARÁ'

Foram avaliadas jabuticabas 'sabará' maduras, acondicionadas em bandejas de polietileno tereftalato, revestidas externamente com filme plástico de PVC, esticável e alto aderente, de 12 e 20 micras, e em bandejas de poliestireno expandido, revestidas externamente com filme plástico de PVC, esticável e alto aderente, de 12 e 20 micras. Cada bandeja recebeu 25 frutos. As bandejas foram armazenadas à temperatura de 11±1ºC com 98%UR e em condições de ambiente (23,6 a 28,3ºC com 53,7 a 68,3%UR). Como controle utilizaram-se frutos acondicionados em bandejas de polietileno tereftalato (12x20x5cm) não recobertas com filme plástico. Considerando-se os resultados obtidos pode-se concluir que o uso de embalagem associada à baixa temperatura reduziu a perda de massa fresca, prolongou a vida-útil dos frutos com manutenção da aparência até 6 dias, não influenciou na evolução dos teores de acidez total titulável, sólidos solúveis totais e pH, mas interferiu na evolução de carboidratos solúveis e vitamina C. Os frutos acondicionados não recobertos com filme plástico e armazenados em condições ambiente resistiram 2 dias, mas ao final não apresentaram aparência aceitável para comercialização, pois haviam emurchecido e enrugado. As condições de refrigeração (11±1ºC) melhoraram a resistência dos frutos acondicionados não recobertos com filmes plásticos, entretanto, após 4 dias apresentaram má aparência.

Dislocation of rotating hinge total knee prostheses. A biomechanical analysis.

Symptomatic instability and implant dislocation are occasionally encountered in patients with a rotating hinge total knee prosthesis. A biomechanical study of rotating hinge total knee implants was performed to determine the association between the design (length and taper) of the central rotational stem and the stability of the implant. The stem lengths and tapers of knee implants made by seven manufacturers were measured. The tilting laxity of each design was tested by measuring the degree of tilting of the central rotational stem within the tibial housing that occurred with increasing amounts of distraction. The maximum amount of distraction that was possible before the stem dislocated was determined for each design. Implant designs with a short and/or markedly tapered central rotational stem had the greatest tilting, laxity, and instability of that stem. The Howmedica, Techmedica, Intermedics/Sulzer Medica, and Wright Medical Technology/ Dow Corning Wright designs required > or = 39 mm of distraction before they dislocated. The Biomet knee implant required 33 or 44 mm of distraction to dislocate, depending on the thickness of the polyethylene tray that was utilized. The S-ROM knee required only 26 mm of distraction before dislocation occurred. The measurements confirmed that the shorter the stem and the greater its taper, the greater the instability and laxity at any given amount of joint distraction.

Avaliação do crescimento de plantas de morangueiro, durante a aclimatização ex vitro

A fim de otimizar a micropropagação de morangueiro cv Campinas, reduzindo as perdas durante a aclimatização, foi realizado este trabalho na Universidade Federal do Rio Grande do Sul. O objetivo foi correlacionar a presença de sacarose no tecido vegetal com a produção de biomassa, na aclimatização. As plântulas desenvolvidas in vitro, após permanecerem três semanas na etapa de enraizamento, em quatro concentrações de sacarose (15, 30, 45 e 60 g L-1), foram transplantadas para bandejas de isopor de 72 células. O delineamento experimental utilizado foi o de blocos casualizados com cinco repetições. Cada parcela constituiu-se de 36 mudas, totalizando 720 plantas. Foram avaliadas as taxas de sobreviventes (%) e de crescimento (mg semana-1), área foliar (cm²), massa seca da parte aérea (mg), área foliar específica (cm² mg-1), razão de massa foliar (mg mg-1) e razão da área foliar (cm² mg mg-1). Estabeleceu - se a dosagem de 45g L-1 de sacarose em meio MS para o cultivo de morangueiro cv Campinas, como a melhor concentração para a produção de biomassa ex vitro. Também foi verificado que essas mudas necessitaram de três a quatro semanas para se adaptarem às novas condições ambientais, e somente após, retomaram o crescimento.

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

ABSTRACTShredded 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&lt;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.

STORAGE QUALITY OF MINIMALLY PROCESSED CABBAGE PACKAGED IN PLASTIC FILMS

ABSTRACTThe effects of packaging and storage at 3C in a refrigerated case on quality changes of minimally processed cabbage were studied. Shredded cabbage samples were packaged in three forms: bags of monooriented polypropylene film (OPP bags) and polyethylene trays overwrapped with a multilayer polyolefin (RD106‐PE tray) or with a plasticized PVC film (PVC‐PE tray). All types of package effectively controlled the weight loss. The modified atmosphere in PVC‐and RD106‐ PE trays did not change more than 3% as compared with normal atmosphere levels. However, in OPP bags, O2 reached 2% and CO2 increased to approximately 13% after 3 days. The microbiological quality during the storage period for all types of packaging was satisfactory. OPP samples were significantly better (p &lt;0.05) in general appearance, wilting and browning but developed an off‐odor. No off‐odor was detected in samples packaged in PVC and RD106‐PE trays. Shelf life for the three packaging forms was estimated.

Effect of High Electric Field on Shelf Life of Strawberries.

An effort was made to elongate the shelf life of strawberries by the application of an alternating current (60 Hz) high electric field (HEF). An internal voltage as high as 174 V was measured in a strawberry by applying a 430 kV/m external electric field. Short treatment periods (0.5-1.5 h) with the HEF (430 kV/m) was found to reduce rotting (%) of the strawberries, but continuous HEF treatment was more effective to control rotting. Because continuous HEF treatment without packaging caused excessive weight loss, the strawberries were packed in polyethylene trays (OPS, P-11) and covered without sealing. The HEF was then continuously applied to the strawberries. Strawberries treated by continuous HEF for 6 days at 20°C and by electric fields of 0, 114, 172, 285 and 430 kV/m resulted in 80, 60, 50, 30 and 0% rotted samples, respectively. No differences were observed in surface color, pH, acidity and sugar contents between treated and non-treated samples.