• Title/Summary/Keyword: physical and microbiological changes

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Physical and Microbiological Changes of Sliced Process Cheese Packaged in Edible Pouches during Storage

  • Ryu, Sou-Youn;Koh, Kyung-Hee;Son, Sook-Mee;Oh, Myung-Suk;Yoon, Jung-Ro;Lee, Won-Jong;Kim, Suk-Shin
    • Food Science and Biotechnology
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    • v.14 no.5
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    • pp.694-697
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    • 2005
  • The objectives of this study were to compare the quality changes of cheese slices individually packed in four kinds of edible pouches in order to select the most suitable variety for individual packaging. The edible Z2 pouch (zein with oleic acid) was selected as maintaining the best cheese qualities based on the physical and microbiological changes undergone by the samples over 4-week storage at $5^{\circ}C$. The cheese sample individually packed in Z2 inner edible pouch and repacked in a plastic (OPP/LLDPE) outer pouch was not significantly different in physical and microbiological changes from that individually packed in a plastic (OPP/LLDPE) inner pouch and repacked in a plastic (OPP/LLDPE) outer pouch. Therefore, it may be concluded on the basis of the physical and microbiological evidence that the Z2 edible pouch can be used as an inner package for cheese slices when it is inside a plastic outer pouch.

Effects of Vessel on the Quality Changes during Fermentation of Kochujang (고추장의 숙성 중 발효 용기가 품질변화에 미치는 영향)

  • Chung Sun-Kyung;Kim Young-Sook;Lee Dong Sun
    • Food Science and Preservation
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    • v.12 no.3
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    • pp.292-298
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    • 2005
  • Kochujang(Korean red pepper paste) of 600 g was fermented in the different types of vessels (glass, polypropylene(PP), polyethylene terephthalate(PET), stainless steel and Korean porcelain called onggi) with 627 mL of volume during 4 months. The quality changes were monitored for physical, chemical and microbiological attributes. Onggi which had high porosity in the micro-structure provided kochujang with higher microbial counts of aerobic bacteria, lactic acid bacteria and yeasts than those of the other containers. Compared to kochujang fermented in the other containers, kochujang in Onggi showed higher protease activity, amino type nitrogen, and free amino acid content. The kochujang in Onggi also attained higher acidity, lower pH and higher reducing sugar concentration than those in the other containers. All changes were completed 2 or 3 months. Onggi showed water loss and salt increase of the kochujang comparable to those in the other vessels, which was from gradual clogging of the micropores during storage. All physical, chemical and microbiological changes made the kochujang in Onggi attain the sensory quality significantly better than those fermented in the other vessels.

Physico-Chemical and Microbiological Changes during Storage of Fresh Ginseng (수삼저장중 이화학적 및 기생물학적 변화)

  • 오훈일;노해원;도재호;김상달;홍순근
    • Journal of Ginseng Research
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    • v.5 no.2
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    • pp.99-107
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    • 1981
  • Physical, chemical and microbiological changes were periodically studied during six-month storage of fresh ginseng under N2, CO2 gas or subatmospheric pressure condition. The results were summarized as follows. 1. The moisture contents of fresh ginseng gradually decreased during the first 2-month storage and thereafter generally reached at equillibrium. 2. There was no significant change in the reducing sugar content in 1-month storage, followed by$.$a decrease in between 2-and 3-month storage. Thereafter, the reducing sugar content increased at the end of 4-month storage. 3. The total sugar content increased significantly during the first 3-month storage. Under CO2 and Nr gas storage, the total sugar content gradually decreased after 3-month storage, while no significant change was observed in the samples stored under subatmospheric Pressure. Amylase activity gradually decreased as storage period increased 4. The content of saponin decreased as storage period increased, but ginsengoide Rf, Rd, Rc and Rb2 increased significantly in 1-month storage. 5. Regardless of storage methods, sprouting of ginseng and growth of microorganisms were inhibited in all samples during the first 4-month storage. However, growth of microorganisms was observed in the rhizome and injured areas of ginseng after 5-month storage in the N2 and CO2 gas atmosphere.

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Physical Methods for the Identification of Irradiated Food

  • Yang, Jae-Seung;Lee, Hae-Jung
    • Preventive Nutrition and Food Science
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    • v.3 no.2
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    • pp.203-209
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    • 1998
  • The development of methods for the identification of irradiated foods helps enforce national and international regulations on labelling to ensure the consumer's free choice to buy irradiated or unirradiated foods. and the availabilityof such methods may assist the promotion of international trade in irradiated food products and help prevent abuse of the technology. A number of approaches to determine the physical , chemical, microbiological and biological changes that occur in foods treated with ionizing radiation have been studied. However no single method is universally applicable. Among physical measurements, the leading methods of indentification are electron spin resonance (ESR) spectroscopy and thermoluminescence(TL). ESR is an established non-destructive method for the analysis of free radicals from their traps and TL is the emission of light from irradiated mineral extracts by heating. Viscosity of carbohydrate polymers by causing chain breaks by irradiation, measuring the impedance of potatoes and detection of gases produced radiolytically are promising techniques for identification purposes. Irradiated water-containing foods show significant supercooling when monitored with a differential scanning calorimeter (DSC), which can be applied to identifying irradiated ones.

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Development of Cooked Rice with Garlic and Astragalus membranaceus Extract for the Health-Friendly Ready-To-Eat Product as Cook-Chill Type

  • Hyeyoon Jeong;Seyoung Ju;Hyeja Chang
    • Journal of the FoodService Safety
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    • v.5 no.1
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    • pp.19-29
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    • 2024
  • Medicinal cooked rice with Astragalus membranaceus extract and garlic was developed as a ready-to-eat product. The response surface methodology was used to examine the effect of garlic and Astragalus membranaceus extract addition on the color, texture, and sensory properties to optimize the product. The product was also analyzed for microbiological, sensory, and physical property changes during storage.As for the color, taste, and overall acceptability, the sensory scores increased with the increase of Astragalus membranaceus extracts (p<0.05). The sensory scores for the product ranged between 9.17~9.92 and foodborne microorganism such as Bacillus cereus, Salmonella, Staphylococcu aureus, and Eschericha coli were not detected after 13 storage days. Therefore, the possible shelf life was evaluated for up to13 days of storage. When considering health and convenience are important factors in the development of new food products, the medicinal and biological effects of garlic and Astragalus membranaceus could be useful for providing healthy diet options for senior consumers. The results of sensory and microbiological tests showed the potential for the commercialization of ready-to-eat cook-chill product as an alternative of cooked rice for Asian populations and Korean senior consumer market.

Identification of Irradiated Foods by Using DNA, Immunochemical, and Biological Methods

  • Kim, Kyeung-Eun;Yang, Jae-Seung
    • Preventive Nutrition and Food Science
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    • v.4 no.4
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    • pp.276-282
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    • 1999
  • Ionizing radiation is considered to be an efficient technology to improve food safety and to extend food shelf-life in the food industry, and it has been used in food processing with a number of attributes. Food labeling should be established to enable the consumer to choose food freely, based on label information. A variety of methodologies to determine the physical, chemical, microbiological, and biological changes due to irradiation has been investigated in order to discriminate the irradiated and unirradiated food products for the consumer's free choice in food selection. However, no satisfactory method has been developed so far. In this review, various approaches based on DNA, immunochemical, and biological methods are addressed.

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Effects of Various Eggshell Treatments on the Egg Quality during Storage

  • Park, Y.S.;Yoo, I.J.;Jeon, K.H.;Kim, H.K.;Chang, E.J.;Oh, H.I.
    • Asian-Australasian Journal of Animal Sciences
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    • v.16 no.8
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    • pp.1224-1229
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    • 2003
  • The combined effects of washing, sanitization and coating of eggshell on the physical and microbiological quality during storage were evaluated at $4^{\circ}$ and $30^{\circ}C$. The interior qualities of the eggs were assessed by weight changes, yolk index, albumen index, Haugh unit value, and microbial contamination of egg shell and egg white during 30 days of storage in untreated, washed, or sanitized and mineral oil-coated eggs. The results suggest that these changes were faster in higher temperature ($30^{\circ}C$) than lower temperature ($4^{\circ}C$) storage, and washed eggs deteriorated faster than untreated eggs. The sanitized and coated eggs maintained the best quality during storage in all parameters measured. The shelf-life of washed, sanitized and coated eggs could be extended 4-5 fold compared to that of washed or untreated eggs.

Determination of Quality Changes throughout Process ing Steps in Chinese-style Pork Jerky

  • Chen, W.S.;Liu, D.C.;Chen, M.T.
    • Asian-Australasian Journal of Animal Sciences
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    • v.17 no.5
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    • pp.700-704
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    • 2004
  • Chinese-style pork jerky is a typical intermediate moisture meat product obtained by curing, drying and roasting pork samples. The chemical, physical and microbiological characteristics of pork jerky were evaluated throughout processing. The moisture content varied from 72.5% to 23.4 or 19.6% and aw varied form 0.97 to 0.74 or 0.72 in accordance with processing steps. The pork jerky roasted at $200^{\circ}C$ had higher shear value than roasted at $150^{\circ}C$ because the moisture content and aw of the former sample was lower than the later sample. The nitrite losses during whole processing steps amount to nearly 50%. The TBA value of pork jerky varied from 0.34 to 9.25 or 9.83 mg of malonaldehyde depended on processing steps. The VBN value of pork jerky ranging from 0.25 to 22.4 or 23.5 mg/kg depended upon processing steps. The ATPase activity of myofibrillar proteins during processing steps were partly or entirely denatured by the heat-drying or heat-roasting treatment. A gradual decrease in microorganism count during processing of pork jerky was also observed.

Fermentation of Kanjang, Korean Soy Sauce, in Porosity-Controlled Earthenwares with Changing the Mixing Ratio of Raw Soils (흙배합비를 달리하여 기공율이 조절된 담금용기 항아리에서의 간장 발효)

  • Chung, Sun-Kyung;Lee, Kwang-Soo;Lee, Dong-Sun
    • Korean Journal of Food Science and Technology
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    • v.38 no.2
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    • pp.215-221
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    • 2006
  • This study focuses on investigating the effect of porosity-controlled earthenware on fermentation of kanjang, Korean soy sauce. Porosity of fermentation vessel was controlled by changing the mixing ratio of raw soils at manufacturing earthenware. Earthenwares contented 0%, 40% and 60% of the mixture of red brown soil and powdered soil (1 : 1), respectively. The more contents of the mixed soil, the more porosity in earthenware. During fermentation of kanjang in porosity-controlled earthenwares at $30^{\circ}C$ for 4 months, physical, chemical, microbiological and sensory quality attributes were monitored. Compared to other containers, kanjang in the earthenware that had 0% mixed soil showed less water loss, salt content and pH. It also produced higher total acidity, protease activity, total nucleotide, and microbiological changes which included total aerobic bacteria, lactic acid bacteria and yeast. Total nitrogen and free amino acids in kanjang did not show the consistency with the mixed soil contents of fermentation containers, which may take more effect of other factors as water loss than the porosity of vessels. However, the percentage of glutamic acid in total free amino acids was a little higher in the earthenware that had 0% of mixed soil than other containers. These positive physicochemical, microbiological changes also resulted in higher sensory quality.

Quality attributes and shelf-life of freshly cut beef coated with waste feather keratin-ginger starch composite enriched with avocado peel polyphenolic-rich extract

  • Olarewaju M Oluba;Samuel I Ojeaburu;Opeyemi A Bayo-Olorunmeke;Georgina Erifeta;Sunday J Josiah
    • Food Science and Preservation
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    • v.31 no.1
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    • pp.1-14
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    • 2024
  • The utilization of coatings composed of bio-based materials in the processing and preservation of meat presents an environmentally conscious, secure, cost-effective, and superior method for prolonging the storage life of meat while also preserving its nutritional value. In this study, changes in physical, chemical, and microbiological characteristics of freshly cut beef coated with distilled water (control) and keratin-starch composites (K-S) functionalized with 0.0-, 0.2-, 0.6-, and 1.0-mL avocado peel polyphenolic-rich extract (APPPE) kept at 4℃ for 12 days were evaluated periodically at 3-day interval using standard techniques. Keratin was extracted from waste feathers, while starch was obtained from ginger rhizomes. Following a 12-day storage period, beef coated with APPPE-enriched K-S composites exhibited a significant (p<0.05) improvement in shelf life by minimizing deteriorative changes in pH and color (as determined by metmyoglobin level) in addition to inhibiting oxidative changes in lipids (as determined by TBARS level) and proteins (protein carbonyl level) in comparison to control and K-S composite without APPPE. Furthermore, microbial growth was significantly (p<0.05) suppressed in meat coated with K-S composite functionalized with APE at 0.6 and 1.0 mL compared to the control. The study suggested that APPPE-enriched K-S composite could offer an eco-friendly and safe food preservation technique for fresh meat.