• Title/Summary/Keyword: physicochemical and sensory characterization

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Characterization of exopolysaccharide-producing lactic acid bacteria from Taiwanese ropy fermented milk and their application in low-fat fermented milk

  • Ng, Ker-Sin;Chang, Yu-Chun;Chen, Yen-Po;Lo, Ya-Hsuan;Wang, Sheng-Yao;Chen, Ming-Ju
    • Animal Bioscience
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    • v.35 no.2
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    • pp.281-289
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    • 2022
  • Objective: The aim of this study was to characterize the exopolysaccharides (EPS)-producing lactic acid bacteria from Taiwanese ropy fermented milk (TRFM) for developing a clean label low-fat fermented milk. Methods: Potential isolates from TRFM were selected based on the Gram staining test and observation of turbid suspension in the culture broth. Random amplified polymorphic DNA-polymerase chain reaction, 16S rRNA gene sequencing, and API CHL 50 test were used for strain identification. After evaluation of EPS concentration, target strains were introduced to low-fat milk fermentation for 24 h. Fermentation characters were checked: pH value, acidity, viable count, syneresis, and viscosity. Sensory evaluation of fermented products was carried out by 30 volunteers, while the storage test was performed for 21 days at 4℃. Results: Two EPS-producing strains (APL15 and APL16) were isolated from TRFM and identified as Lactococcus (Lc.) lactis subsp. cremoris. Their EPS concentrations in glucose and lactose media were higher than other published strains of Lc. lactis subsp. cremoris. Low-fat fermented milk separately prepared with APL15 and APL16 reached pH 4.3 and acidity 0.8% with a viable count of 9 log colony-forming units/mL. The physical properties of both products were superior to the control yogurt, showing significant improvements in syneresis and viscosity (p<0.05). Our low-fat products had appropriate sensory scores in appearance and texture according to sensory evaluation. Although decreasing viable cells of strains during the 21-day storage test, low-fat fermented milk made by APL15 exhibited stable physicochemical properties, including pH value, acidity, syneresis and sufficient viable cells throughout the storage period. Conclusion: This study demonstrated that Lc. lactis subsp. cremoris APL15 isolated from TRFM had good fermentation abilities to produce low-fat fermented milk. These data indicate that EPS-producing lactic acid bacteria have great potential to act as natural food stabilizers for low-fat fermented milk.

Effect of Corona Discharge on the Changes in Quality and Pasteurization of Ginseng Powder (코로나방전 처리 인삼분말의 살균효과 및 품질변화)

  • Kim, Kyung-Tack;Kim, Sung-Soo;Ha, Sang-Do
    • Korean Journal of Food Science and Technology
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    • v.35 no.6
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    • pp.1237-1243
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    • 2003
  • As a newly emerging pasteurization method for improving the shelf-life of powdered ginseng, the corona discharge generated at high voltage conditions was examined for its effects on microbial pasteurization, physicochemical characterization, and sensory evaluation. The pasteurizing effects of corona discharge on total bacteria, yeast, molds, and coliforms increased with increasing voltage. However, corona discharge treatment of 5 kv/cm did not show significant effects of pasteurization on the yeast, molds, and coliforms. Treatment with 20 kv/cm reduced about 95% of the total bacteria $(6.14{\pm}0.04{\rightarrow}\;4.59{\pm}0.04$) and coliforms ($2.43{\pm}0.05{\rightarrow}\;1.00{\pm}0.05$) and 99% of the yeast and molds ($4.65{\pm}0.06{\rightarrow}\;2.73{\pm}0.06$). The proximate analysis, minerals, free sugars, crude saponin, and colors of the control ginseng and the ginseng treated with 20 kv/cm were not significantly different at p<0.05. Corona discharge of up to 20 kv/cm did not affect the proximate analysis, minerals, free sugars, crude saponin, and colors of the powdered ginseng. Sensory evaluation scores on color, flavor, taste and overall acceptability between the control ginseng and ginseng treated with 20 kv/cm corona discharge were not significantly different at p<0.05 level. Consequently, corona discharge treatment is thought to be a good alternative pasteurization method for improving the shelf-life of powdered ginseng due to its effective pasteurization, maintenance of nutrients and good sensory characteristics.

Preparation and Characterization of Physicochemical and Sensory Properties of Hwajeon Added with Wild Grape Extract (머루즙 첨가가 화전의 이화학적.관능적 특성에 미치는 영향)

  • Lee, Byung-Yong;Kim, Nam-Ho;Kim, Sol-I;Kim, Seul-Gi;Kim, Jin-Sun;Surh, Jeong-Hee
    • Korean Journal of Food Science and Technology
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    • v.43 no.5
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    • pp.588-596
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    • 2011
  • Wild grape extract (WGE) was added into hwajeon at different concentrations (0, 5, 15, 30, 50% of water). The resulting hwajeon were analyzed for their physicochemical and sensory properties. With increasing concentrations of WGE, the pH of dough and hwajeon decreased, and their degrees brix and color intensity increased, presumably due to the presence of tartaric acid, sugar, and anthocyanin in the WGE. The WGE-enriched hwajeon showed higher hardness, gumminess, and chewiness than control hwajeon, which might have been because the sugar and tartaric acid in the WGE partially inhibited starch gelatinization during heat processing. Nevertheless, all the sensory properties and preference were higher in WGE-enriched hwajeon than controls, which could be partially attributed to the fact of that the WGE-enriched hwajeon retained relatively higher moisture. It is suggested that WGE-enriched hwajeon with high preference could be prepared without loss of hwajeon quality.

Preparation and Characterization of Physicochemical and Sensory Properties of Bread Enriched with Two Types of Wild Grape Extract (제조방법이 다른 두 종류의 머루즙 첨가가 빵의 이화학적 및 관능적 특성에 미치는 영향)

  • Lee, Byung-Yong;Lee, Malp-Eum;O, Jin-Hwan;Kim, Eun-Cho;Surh, Jeong-Hee
    • Korean journal of food and cookery science
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    • v.26 no.5
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    • pp.636-648
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    • 2010
  • Two types of wild grape extracts(WGE) prepared by different methods were added into butter-top bread at different concentrations(0, 5, 10, 15, 20% of water). Then, the resulting breads were analyzed for their physicochemical and sensory properties in order to identify whether or not the WGE-enriched breads were comparable to control bread in terms of qualities and preferences. Wild grape sugar mixture(WGS), which was prepared by osmotic dehydration of wild grape fruits with the same amounts of sugar, presented significantly lower moisture content and titratable acidity as well as higher pH and sugar content compared to wild grape juice(WGJ), which was produced by boiling the fruits in a vacuum jar and squeezing. The pH of the doughs and breads containing WGE tended to decrease with increasing amounts of WGE, and this phenomenon was more appreciable in those containing WGJ than WGS. This was presumably due to the higher contents of tartaric acid in WGJ. For both types of extracts, hardness, gumminess, and chewiness of the doughs decreased with the addition of WGE, nevertheless, which properties were not remained in the resulting breads. This could be partially attributed to the relatively high degree of baking loss and lower pH of the WGE-enriched breads than those of control bread. Contrary to the mechanical analyses, the sensory properties of the breads were dependent on the WGE type. That is, WGJ-enriched bread showed lower consistency and moistness than control bread, which consequently led to relatively lower overall acceptability. However, WGS addition did not adversely affect the sensory properties of the bread. In particular, addition of 5% WGS somewhat improved the physical and sensory qualities of the bread. Thus, WGE-enriched bread could be produced without loss of bread quality when prepared with 5% WGS.

Preparation of fermented vinegars using mushroom mycelial cultures and characterization of their physicochemical properties (버섯 균사체를 이용한 발효 식초 제조 및 이화학적 특성)

  • Kim, Jeong-Han;Baek, Il-Sun;Shin, Bok-Eum;Lee, Yong-Seon
    • Journal of Mushroom
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    • v.17 no.4
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    • pp.230-234
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    • 2019
  • This study was conducted to prepare healthy vinegars using the mycelia of various mushrooms (Cordyceps militaris, Phellinus baumi, Pleurotus cornucopiae, and Ganoderma lucidum). Analyses of the bioactive components of these vinegars revealed that those prepared using mushroom mycelial cultures on fermented brown rice had increased bioactive component levels compared to those cultured on unfermented brown rice. The highest beta-glucan contents (78.7 mg/g) were found in P. baumi cultures and 0.34mg/g of cordycepin was detected in C. militaris cultures. Regarding the chemical properties of these mushroom mycelia vinegars (MMVs), those prepared using C. militaris and P. cornucopiae cultures showed higher acidity and reduced sugar content. Sensory assessments of C. militaris and P. cornucopiae MMVs yielded scores of 7.3 and 6.6, respectively. Analyses of bioactive components revealed that C. militaris MMV contained high levels of polyphenols and 786 mg/L of cordycepin. P. cornucopiae MMV contained the highest amount of beta-glucan (20.9 mg/g).

Preparation and Characterization of White Bread with Sweet Persimmon (단감을 첨가한 식빵의 제조 및 특성)

  • Oh, Won-Gyeong;Kim, Ju-Hee;Lee, Seung-Cheol
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.40 no.2
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    • pp.253-258
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    • 2011
  • To increase utilization of Korean sweet persimmon, white breads containing sweet persimmon were prepared and those characterizations were evaluated. WB (white bread without persimmon), FPB (white bread containing 30% (w/w) persimmon flesh), and WPB (white bread containing 30% (w/w) whole persimmon) were prepared by straight dough method. Specific volumes of WB, FPB, and WPB were 3.51, 2.99 and 3.21 $cm^3$/g, respectively. Loss of bread of WB, FPB, and WPB were 9.81, 7.78, and 8.86%. With addition of sweet persimmon in bread, the lightness (L) was decreased, and the redness (a) and the yellowness (b) were increased. DPPH radical scavenging activity, one of antioxidant activity, of WB, FPB, WPB at concentration of 10 mg/mL was $12.39{\pm}0.135$, $14.57{\pm}0.01$, and $19.57{\pm}0.44%$, respectively. Total phenolic contents of WB, FPB and WPB were $177.05{\pm}5.52$, $185.26{\pm}0.79$, and $216.24{\pm}5.47$ mg GAE/g. Hardness of WB were 175.33 Dyne/$cm^3$, and the value was decreased in FPB and WPB. In sensory test, FPB acquired relatively high points in texture, flavor, taste, and overall acceptance.