• 제목/요약/키워드: browning

검색결과 938건 처리시간 0.075초

마른멸치 저장중의 수분활성과 비효소적 갈변반응 (NON-ENZYMATIC BROWNING REACTIONS IN DRIED ANCHOVY WHEN STORED AT DIFFERENT WATER ACTIVITIES)

  • 한성빈;이종호;이강호
    • 한국수산과학회지
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    • v.6 no.1_2
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    • pp.37-43
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    • 1973
  • In this paper, non-enzymatic browning reactions as a factor of self stability of boiled and dried anchovy were studied to discuss the effect of water activity to the discoloring reaction and the preservative moisture content. The development of rancidity of the fish meat was also mentioned since the fish is fatty and the lipid oxidation is a functional deteriorative reaction. Fresh anchovies were boiled in $10\%$ salt solution immediately after the catch, sun dried, and stored at room temperature ($20^{\circ}C$) for two months in humidistat chambers maintaining different levels of water activity as described in Table 1. The pigments formed by non-enzymatic browning reations were extracted in two fractions, those were chloroform-methanol soluble and water dialyzed fraction, and analyzed spectrophotometrically at the wavelength of 460 nm. These two fractions were considered, respectively to be the brown pigments formed by lipid oxidation reactions for the formler and for the latter, to be the pigments developed by sugar-amino or Maillard reaction. The oxidation of lipid in anchovy meat during the storage was measured as the changes in Peroxide value and the color development of thiobarbituric acid reaction. It is summarized from the results that the rate of both reactions, lipid oxidation and browning, was affected by water activity levels. In regard to the changes in peroxide and TBA value during the storage, the propagation of lipid oxidation was obviously accelerated at lower humidities whereas the development of browning progressed at the higher. These two reactions occurring simultaneously and contrary in activity resulted in that the rate of deterioration occurring oxidatively or by browning, was the minimum at the water activity of 0.32-0.45 which were $7-9\%$ as moisture content and slightly higher value than that of monolayer (Aw=0.21, $5.11\%$ as moisture content). It is also noted that the lipid oxidative browning was presumed to dominate sugar-amino reactions so that the rate of browning of the meat was ultimately depended on the development of rancidity although sugar-amino reactions initiated earlier than the other at the first ten days of storage, particulary at higher humidity. At the lower humidity sugar-amino reactions were occurred gradually but lower levels in color development in contrast to the consistent increase in lipid oxidative browning.

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Effect of pH on the Enolization of Sugars and Antioxidant Activity of Caramelization Products Obtained by Caramelization Browning

  • Kim, Ji-Sang;Lee, Young-Soon
    • Food Science and Biotechnology
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    • v.17 no.5
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    • pp.931-939
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    • 2008
  • The objective of this study was to investigate the enolization reaction and the antioxidant activity of caramelization products (CPs) obtained by caramelization browning of glucose and fructose solutions prepared at a pH ranging from 7.0 to 12.0 at varying temperatures ($80-180^{\circ}C$). The degradation of sugars rapidly increased at a high alkaline pH (10.0-12.0), and fructose degraded more rapidly than glucose (p<0.05). As the pH increased, the degree of sugar enolization was higher in fructose than in glucose. Browning and the formation of intermediate degradation products increased with the increase in heating temperatures. The browning development was dependent upon the type of sugar, and it was generally higher at alkaline pH than at neutral pH. The reducing power and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity of the CPs increased with the increase in browning and formation of large amounts of intermediates. Therefore, the CPs with pronounced antioxidant activity can be prepared by heating fructose or glucose solutions that have a very alkaline pH to high temperatures.

Inhibition of Polyphenol Oxidase and Peach Juice Browning by Onion Extract

  • Kim, Choon-Young;Kim, Mi-Jeong;Lee, Min-Young;Park, In-Shik
    • Food Science and Biotechnology
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    • v.16 no.3
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    • pp.421-425
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    • 2007
  • The inhibitory effect of onion extract on polyphenol oxidase (PPO) and browning of peach juice was investigated. Various reducing agents such as L-ascorbic acid, L-cysteine, dithiothreitol, glutathione, and sodium pyrosulfite strongly inhibited polyphenol oxidase extracted from peach. The enzyme was also inhibited by addition of water extract of onion. Regardless of substrates used, the addition of heated onion extract exhibited stronger inhibitory effect on peach polyphenol oxidase activity than that of the fresh one. The inhibitory effect of onion extract was dependent on heating temperature and time. The onion extract inhibited the peach polyphenol oxidase non-competitively. The heating of onion extract in the presence of glucose, glycine stimulated the inhibitory effect of the onion extract, which suggests non-enzymatic browning products produced during heating might be responsible for the stronger inhibitory action of the heated onion extract. The retardation of peach juice browning by onion extract seems to be caused by inhibition of peach PPO.

Pathological Properties of Cryptococcus pseudolongus on the Mycelia and Fruit Body of Lentinula edodes

  • Kwon, Hyuk Woo;Kim, Seong Hwan
    • Mycobiology
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    • v.49 no.2
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    • pp.173-182
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    • 2021
  • Recently, Cryptococcus pseudolongus has been reported as a new pathogen of shiitake (Lentinula edodes). However, its pathological properties are not much known. To further understand its impact on the mushroom, we investigated the pathogen's interactions with the mycelium of shiitake, histopathological properties, host range, and sensitivity to diverse antifungal agents. The strain C. pseudolongus DUCC 4014 inhibited the mycelial growth of L. edodes strain (cultivar Sanjo 701ho) and caused browning in the mycelia confronted with the yeast on PDA. Spray inoculation of the yeast caused an abnormal browning symptom on the cap and/or gills of three shiitake cultivars grown on sawdust media in vinyl bags. Scanning electron microscopic images of the abnormally browned parts of shiitake fruit body illustrated that mushroom tissues were loosed and dispersed in the middle and edge of the cap and the arrangement of basidiospores borne on basidia in the gills was disturbed compared to those of normal shiitake fruit body. Spray inoculation also led to developing abnormal browning on the harvested fruit body, indicating C. pseudolongus could be a problem during mushroom storage. But the yeast was not able to induce abnormal browning on mushrooms of Pleurotus ferulae, Pleurotus fostreatus, and Agaricus bisporus. But it induced browning only on button mushroom (A. bisporus) when they were inoculated after wounding. Tests with 16 kinds of fungicides revealed that the cell growth of C. pseudolongus could be inhibited by benzalkonium chloride at MIC 7 ㎍/ml and benomyl at MIC 3 ㎍/ml.

건조과정 중 갈변에 의한 양파가루의 항산화 특성 연구 (Enhancement of Antioxidant Activity of Onion Powders by Browning during Drying Process)

  • 이동진;한정아;임승택
    • 한국식품과학회지
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    • v.48 no.1
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    • pp.15-19
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    • 2016
  • Drying process was applied to increase the antioxidant activity of onion powder: freeze-drying or air-drying at 50, 70, and $90^{\circ}C$ and onion extracts were obtained from each powder using water or aqueous ethanol (50%) at $25^{\circ}C$ and $60^{\circ}C$. In the color analysis, the freeze-dried powders showed higher $L^*$ and lower $a^*$ and $b^*$ values than did the air-dried ones. The browning index of powders air-dried at $90^{\circ}C$ was significantly higher than that of freeze-dried powders or those air-dried at temperatures below $90^{\circ}C$. Phenolic content in the extracts was 4.02-23.12 mg gallic acid equivalent/g sample, and was the highest in the extract from the sample air-dried at $90^{\circ}C$, regardless of the extraction condition. The highest antioxidant activity, measured by 2,2-azinobis-3-ethylbenzothiazoline-6-sulfonic acid and 1,1-diphenyl-2-picrylhydrazyl methods, was found in the powder air-dried at $90^{\circ}C$, which induced browning. These findings indicate that antioxidant activity depends more on browning during drying than on extraction conditions.

Effects of Temperature, Illumination, and Sodium Ascorbate on Browning of Green Tea Infusion

  • Ye, Qian;Chen, Hao;Zhang, Lin Bin;Ye, Jian Hui;Lu, Jian Liang;Liang, Yue Rong
    • Food Science and Biotechnology
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    • v.18 no.4
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    • pp.932-938
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    • 2009
  • Browning of tea infusion is an obstructive factor influencing shelf life of ready-to-drink green tea. Effects of temperature and illumination on the browning of green tea infusion were investigated. It was shown that both elevated temperature and illumination led to the browning of green tea infusion, but temperature had greater effect on infusion color and level of catechins than illumination. The levels of unoxidized catechins such as (-)-epigallocatechin gallate (EGCg), (-)-epigallocatechin (EGC), (-)-epicatechin gallate (ECg), (-)-epicatechin (EC), and total catechins remaining in the tea infusion were significantly correlated to color parameters of the tea infusion. Sodium ascorbate inhibited the infusion browning by suppressing the oxidation of tea catechins and it is considered to be a more suitable preservative for prolonging shelf life of ready-to-drink green tea than ascorbic acid because it has less effect on tea taste. The effects of temperature and illumination on the epimerization of catechins were also discussed.

Efficacy of Sodium Hypochlorite and Acidified Sodium Chlorite in Preventing Browning and Microbial Growth on Fresh-Cut Produce

  • Sun, Shih-Hui;Kim, Su-Jin;Kwak, Soo-Jin;Yoon, Ki-Sun
    • Preventive Nutrition and Food Science
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    • v.17 no.3
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    • pp.210-216
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    • 2012
  • The use of suitable sanitizers can increase the quality of fresh-cut produce and reduce the risk of foodborne illnesses. The objective of this study was to compare the washing effects of 100 mg/L sodium hypochlorite (SH) and 500 mg/L acidified sodium chlorite (ASC) on the prevention of enzymatic browning and the growth of microbial populations, including aerobic plate counts, E. coli, and coliforms, throughout storage at $4^{\circ}C$ and $10^{\circ}C$. Fresh-cut zucchini, cucumbers, green bell peppers, and root vegetables such as potatoes, sweet potatoes, carrots, and radishes were used. Compared to SH washing, ASC washing significantly (p<0.05) reduced microbial contamination on the fresh-cut produce and prevented browning of fresh-cut potatoes and sweet potatoes during storage. More effective inhibition of aerobic plate counts and coliforms growth was observed on fresh-cut produce treated with ASC during storage at $10^{\circ}C$. Polyphenol oxidase (PPO) activity of fresh-cut potatoes and sweet potatoes was more effectively inhibited after washing with ASC. The use of 500 mg/L ASC can provide effective antimicrobial and anti-browning treatments of fresh-cut produce, including processed root vegetables.

마른 오징어의 품질평가 및 보존기간 (Quality Evaluation and Shelf-life of Dried Squid)

  • 유병진;이강호
    • 한국수산과학회지
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    • v.21 no.3
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    • pp.169-176
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    • 1988
  • In order to obtain the objective indices which can assess the quality and the shelf-life of dried squid, nonenzymatic browning, carbonyl value, trimethyl amine (TMA) and trimethyl amine oxide (TMAO) decrease and panel test were determined in dried squid at various water activity levels. When the data of nonenzymatic browning fit a zero order equation, $r^2$ value were more than 0.92 except aw 0.52 for 0.8241. Through variance analysis for the data of browning extent and TMAO decrease, the confidence limits of regression equation were $99\%$ and their limit values of shelf-life were shown 0.45390 O. D./g. solid and 190.322 g/g respectively. In case of TMAO, $r^2$ value was calculated more than 0.95. Linear regression equation for the correlation between browning data and average panel score was Y=0.6138-0.053X and its $r^2$ value was 0.9285. Also in TMAO decrease, the equation was InY=2.0314+0.08269x and $r^2$ value was 0.7854. The shelf-life, evaluated by nonenzymatic browning, TMAO decrease and panel test, was 110-170 days at aw 0.45-0.76 except aw 0.15.

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Effect of Edible Coatings Containing Soy Protein Isolate (SPI) on the Browning and Moisture Content of Cut Fruit and Vegetables

  • Shon, Jin-Han;Choi, Yong-Hwa
    • Journal of Applied Biological Chemistry
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    • v.54 no.3
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    • pp.190-196
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    • 2011
  • Effectiveness of edible coatings containing soy protein isolate (SPI), in reducing oxidative browning and moisture loss during storage ($4^{\circ}C$) of cut apples, potatoes, carrots, and onions was investigated. The SPI coatings were shown to have antioxidative activity. Furthermore, addition of carboxymethyl cellulose (CMC) to the formulations significantly improved its antioxidative activity. Oxidative discoloration, as determined by Commission Internationale De I'Eclairage (CIE) lightness ($L^*$), redness ($a^*$), and yellowness ($b^*$) color scale, was significantly reduced (p <0.05) by SPI coating treatments over a storage time of 120 min. Loss of lightness was reduced by SPI coatings with and without CMC. These respectively showed 4.03 and 3.71% change of $L^*$ value compared to 8.56% for control. Browning of the control in cut potatoes was significantly increased by 106.6% in contrast to 34.3 and 35.2% for SPI coatings with and without CMC, respectively. The $b^*$ values also reflected effectiveness of SPI. Moisture barrier effect was significantly better for the treatments, compared to the control. SPI coatings reduced moisture loss in apples and potatoes, respectively, by 21.3 and 29.6% over the control. Cut onions did not show any treatment effect both in terms of browning and moisture loss. SPI coatings prove to be good moisture barrier and antioxidative property.

간장 Model System에서 산소의 갈변촉진효과 (Stimulatory Effect of Oxygen on the Browning of a Soy Sauce Model System)

  • 박승규;경규항
    • 한국식품과학회지
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    • v.23 no.4
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    • pp.523-525
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    • 1991
  • 18%의 염용액에 glucose와 glycine을 혼합하여 만든 간장 model system에서 산소가 갈변에 미치는 영향을 연구하였다. 간장 model system을 혐기적으로 저장하였을 때에는 갈변이 $13.2\;OD_{490}$이었던 것에 비해 호기적상태에 저장하였을 때는 $27.0\;OD_{490}$으로서 약 두배의 갈변이 관찰되었다. 이와 같이 산소의 존재가 갈변을 촉진시키는 현상은 유기산을 첨가한 시험구에서도 마찬 가지였다.

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