Polyethylene Terephthalate Containers Research Articles

생대추의 저장성에 미치는 포도송이줄기 추출물 처리의 효과

포도추출물 처리가 생대추의 저장에 미치는 영향을 살펴보기 위하여 50 및 70% 숙도의 생대추를 PE와 PET 용기에 넣고 trans-resveratrol 함량이 10, 30 및 50 ppm이 되도록 포도추출물을 처리하여 0℃에서 저장하면서 에틸렌가스, 부패율 및 이화학적 특성을 측정하였다. 에틸렌가스의 함량은 대부분의 처리구에서 저장 8주까지는 증가하는 경향을 나타내다가 그 이후부터 점차 감소하는 경향을 나타내었다. 부패과는 대조구의 경우 6~8주차에서 서서히 발생한 반면 숙도 50%, PE 용기, 10 ppm 처리구의 경우는 저장 14주 이상에서 발생하기 시작하였다. 가용성 고형분은 저장 초기 23.0~25.8˚Brix 범위였으며, 저장기간 중 약간 증가하였다. 경도는 저장 2~4주까지는 소폭 증가한 후 감소하였으며, 70% 숙도의 대추보다 50% 숙도의 대추가 더 오래 높은 경도를 유지하였다. 총산은 0.0912~0.0988% 범위였고, 저장기간 동안 약간 증가하였으며, 50% 숙도의 대추보다 70% 숙도의 대추가 높은 함량을 보였고 포도추출물의 영향은 거의 없는 것으로 나타났다. 비타민 C 함량은 저장 전 숙도에 따라 31.47~67.78 ㎎/100 g 범위였으며, 저장 2~4주에 가장 높은 함량(197.3~273.4 ㎎/100 g)을 보인 후 감소하였으며, 50% 숙도의 대추보다 70% 숙도의 대추가 높은 함량을 보였다. 본 실험결과 생대추의 저장은 0℃에서 10~12주까지 가능한 것으로 판단되었으며, 숙도 70% 대추보다는 숙도 50% 대추가, PET 용기보다는 PE 용기가 약 2주 정도 저장기간이 길게 나타났다. 또한 포도추출물 처리는 trans-resveratrol 함량 10 ppm 처리구가 가장 양호하게 나타났다.

Volatile Compounds and Chemical Changes in Ultrapasteurized Milk Packaged in Polyethylene Terephthalate Containers

ABSTRACTThe volatile compounds profile and chemical stability of ultrapasteurized 2% milk bottled in amber polyethylene terephthalate (PET) were studied along with its shelf life of 60 d at 5 °C. Identification of volatile compounds using a solid‐phase microextraction (SPME) technique with gas chromatography‐mass spectrometry was performed in situ in the commercial product. Chemical stability was determined by measuring dissolved oxygen, free sulfhydryl groups, ascorbic acid, and headspace oxygen. The classes of volatile compounds identified were ketones, aldehydes, hydrocarbons, fatty acids, alcohol, and miscellaneous compounds. Volatile compounds found consistently during the storage period were 2‐heptanone, methoxy‐phenyl‐oxime, decane, 1‐ethyl‐2,4‐dimethyl‐benzene, D‐limonene, 2‐nonanone, octanoic acid, dodecane, and 4‐(1,1,3,3, ‐tetramethylbutyl) phenol. Possible products of lipid oxidation, such as hexanal, octanal, and nonanal, were also positively identified. Chemical stability of PET‐bottled milk was demonstrated by the insignificant changes in pH or TA, with the exception of ascorbic acid concentration, which degraded in the product at 60 d of refrigerated storage. Sensory evaluation of the milk samples revealed that there is no noticeable oxidized or rancid off‐flavor at 60 d of storage.

Processamento mínimo de uvas de mesa sem semente

O trabalho teve como objetivo avaliar os aspectos qualitativos de uvas de mesa apirênicas (sem sementes) quando submetidas ao processamento mínimo e armazenadas sob refrigeração. Para tanto, foram utilizadas uvas da cultivar BRS Morena e da Seleção Avançada nº 8, produzidas na Embrapa Uva e Vinho/Estação Experimental de Viticultura Tropical (da Embrapa de Jales). Os cachos, depois de higienizados, imersos em água clorada a 300 mg de cloro.L-1 por 5 min., foram mantidos em câmara fria, a 12ºC, por 12 h. Pessoas treinadas e com proteção adequada procederam à degrana dos cachos e ao posterior enxágüe das bagas com água clorada (20 mg.L-1) a 12ºC. Depois de escorrido o excesso de água, as bagas foram acondicionadas em bandejas de tereftalato de polietileno (PET) transparente com tampa e com capacidade para 500 mL. Cada unidade, contendo 200 g de bagas, foi armazenada a 2,5 ± 1ºC e 88% UR por até 36 dias. Avaliaram-se a perda de massa fresca, a evolução da aparência, a coloração e os teores de sólidos solúveis totais (SST), e de acidez titulável (AT). Nas condições do experimento, os produtos minimamente processados da cv. BRS Morena e da Seleção 8 apresentaram baixa perda acumulada de massa fresca (0,16%). O produto da cv. Morena apresentou-se mais escuro (L = 25,04) e mais arroxeado (h° = 332,88) que o da Seleção 8 (L = 29,86 e h° = 345,11), propiciando-lhe melhor qualidade visual. O suco da 'BRS Morena' apresentou maiores teores de SST (22,17 °Brix) e menores para a AT (0,56 %), o que resultou em uma relação SST/AT maior e melhor (39,76) que o da Seleção 8 (18,81). A cv. BRS Morena também apresentou boa manutenção da aparência e, portanto, da qualidade comercial, por 33 dias a 2,5°C, superior ao obtido para a Seleção 8 (24 dias).

Processamento mínimo em goiabas 'Paluma' e 'Pedro Sato': 2. Avaliação química, sensorial e microbiológica

Two cultivars of guava fruit, and Paluma, were studied. They were both obtained from a commercial orchard, at the maturation stage of ready for harvest, corresponding to a dull-green coloration and considered perfect for eating. The fruits were initially immersed in a solution of sodium hypochlorite (150mg.L-1 chlorine) for 5 min, for superficial disinfection. Trained personnel, using adequate protection and disinfected equipment, peeled the fruits, cut them longitudinally down the middle and removed the pulp with the seeds, at a temperature of 12°C. After rinsing with chlorinated water (20mg.L-1 chlorine) the fruit halves were packaged in polyethylene terephthalate containers. These units were stored at 3°C for 10 days. Microbiological analyses were performed throughout the study. Chemical analyses of the products were carried out to determine the contents of lignin, ascorbic acid, total titratable acidity, total soluble solids and the percentage of solublized pectin, in addition to testing for the sensory variables of texture, flavor and preference. For both cultivars the texture became more fragile and the ascorbic acid content reduced during the storage period. During this period there was an increase in lignin content and no change in total soluble solids (TSS) content, total titratable acidity (TTA) and the TSS/TTA ratio. The product of the Pedro Sato cultivar showed less loss of texture than that of 'Paluma,' considered by the tasters as the one with more flavor and thus being more preferred. Because of the hygiene precautions taken during the processing of the product, it showed a lower microbial contamination (< 103 CFU.g-1), in all the tests conducted.

Shelf-life of Milk Packaged in Plastic Containers With and Without Treatment to Reduce Light Transmission

The effect of prolonged light exposure on the chemical changes in milk stored at 4°C in clear polyethylene terephthalate (PET) bottles was compared with milk stored in green PET bottles, containers made from PET incorporating a UV blocker, PET containers with exterior labels and high-density polyethylene (HDPE) jugs and low-density polyethylene (LDPE) pouches stored under the same conditions. Data were obtained for lipid oxidation, vitamin A degradation, protein hydrolysis, lipolysis and microbial growth. The milk stored in green PET bottles experienced less lipid oxidation and vitamin A loss than milk stored in the clear PET bottles, or the LDPE pouches and jugs. In general, the milk stored in the clear PET bottles was not as well protected from the effects of light as milk stored in green bottles or LDPE pouches. However, during the first week of storage, only vitamin A loss showed a substantial difference between the milk stored in green PET bottles, clear PET bottles or LDPE pouches. The PET bottles with UV blockers slowed vitamin A degradation but had little effect on lipid oxidation. Blocking visible light with translucent labels helped to inhibit lipid oxidation and vitamin A degradation.

Stability of ramipril in water, apple juice, and applesauce

The stability of ramipril in water, in apple juice, and in applesauce was studied. The contents of a single capsule each of ramipril 1.25, 2.5, and 5 mg were mixed in glass beakers with 120 mL of deionized and filtered water, apple juice, or applesauce. Each mixture was apportioned into 10 120-mL amber polyethylene terephthalate (PET) containers. Five of the containers in each set were stored at 23 degrees C, and samples were taken at 0, 1, 2, 6, 12, and 24 hours. The other five containers were stored at 3 degrees C, and samples were taken at 4, 8, 12, 24, and 48 hours. The samples were analyzed for ramipril concentration by stability-indicating high-performance liquid chromatography (HPLC). The quantity of drug remaining in the PET container after "administration" was determined by mixing the contents of single 5-mg ramipril capsules with 60 mL of apple juice, pouring the mixture into a waste receptacle, rinsing the PET container three separate times with 10 mL of water, and analyzing the pooled fluid from these rinses for ramipril concentration by HPLC. Under no condition did the percentage of ramipril remaining drop below 90%. No peaks for degradation products appeared in the chromatograms. The mean +/- S.D. quantity of ramipril remaining in the PET containers after draining was 0.3 +/- 0.3% for the apple juice. Ramipril from 1.25-, 2.5-, and 5-mg capsules mixed in water, in apple juice, and in applesauce was stable for 24 hours at 23 degrees C and for 48 hours at 3 degrees C.

The Sterile Filtration and Packaging of Beer into Polyethylene Terephthalate Containers

The Sterile Filtration and Packaging of Beer into Polyethylene Terephthalate Containers

The Sterile Filtration and Packaging of Beer into Polyethylene Terephthalate Containers

This paper describes the successful practical development of a system for the sterile filtration and aseptic packaging of beer into 2-L polyethylene terephthalate (PET) bottles. The major factors resulting in poor filterability were found to be colloidal carbohydrates and the use of coarse grades of kieselguhr in a single-pass filtration regime. The filterability of the beer through high-capacity prefilters followed by 0.45-μm Millipore membrane filters was greatly improved by addition of μ-glucanase in the mash tun and optimization of the single-pass kieselguhr filtration. Microbiological stability of the beer was achieved primarily by filtration through 0.45-μm Durapore membranes and secondly by adherence to stringent quality assurance procedures with regard to the filling operation. Although the specification of nil microorganisms in the bottle was not always achieved, no beer spoilage was observed. These microorganisms possibly found ingress through contaminated bottles and closures. Our experience supports the findings of similar operations showing that the success of sterile filtration and aseptic packaging lies in good “quality assurance” procedures.

Use of PET Bottles for Wine

Two separate studies, each covering a year of testing, indicated that comparison of wine bottled in polyethylene terephthalate (PET) to that bottled in glass would depend on the size of the PET container and whether a high barrier material was used as an additional layer of protection. Wine in 3-L PET containers with a Saran layer or 4-L PET containers maintained quality for 10 to 12 months when compared to the same wine in glass containers. Changes in SO₂ and color were the most obvious measurable changes. These were due to oxygen permeation. Keeping the level of free SO₂ at <i>ca</i> 30 mg/L was effective for the preservation of the samples of white wine studied. Data are presented showing the important measurable changes over the sampling period.

Thermoplastic polyester resins for containers

AbstractAn overview of the use of polyesters for containers is presented. The market for polyethylene terephthalate container resin should reach 760 million pounds by 1989. Diethylene glycol, a polymerization by‐product, and other comonomers reduce the polymer melting point and crystallization tendency, yielding wider container processing latitude. The effect of these modifications on creep and tensile strength is discussed. Improved gaseous barrier approaches and hot‐fillable container opportunities are presented, Newer applications for thermoplastic polyester containers are summarized.