• Culinary science and hospitality research
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• v.20 no.5
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• pp.71-75
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• 2014

The purpose of this study is to verify antecedent variables that affect emotional labor. The results are as follows. First, display rules positively affected deep acting and negatively affected surface acting. Second, customer contact time positively affected deep acting but did not affect surface acting. Third, the interaction between display rules and customer contact time did not have significant effects on surface acting but negatively affected deep acting. The implications based on these results are as follows. First, theoretically, this study extends the range of leading variables that affect emotional labor and verifies the moderation effects between these variables. Next, practically, this study suggests that presenting harmonious criteria with regards to display rules and customer contact time that fit well into the concept of food service company is a very useful tool to manage emotional labor of the employees. The limitation of this study is that the causal relationship between variables demonstrated in this study cannot be generalized due to convenience sampling and cross sectional research.

• Food Science of Animal Resources
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• v.36 no.3
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• pp.427-434
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• 2016

Benzoic acid is occasionally used as a raw material supplement in food products and is sometimes generated during the fermentation process. In this study, the production of naturally occurring yogurt preservatives was investigated for various starter cultures and incubation temperatures, and considered food regulations. Streptococcus thermophilus, Lactobacillus acidophilus, Lactobacillus delbrueckii subsp. bulgaricus, Lactobacillus rhamnosus, Lactobacillus casei, Lactobacillus paracasei, Lactobacillus reuteri, Lactobacillus plantarum, Bifidobacterium longum, Bifidobacterium lactis, Bifidobacterium bifidum, Bifidobacterium infantis, and Bifidobacterium breve were used as yogurt starter cultures in commercial starters. Among these strains, L. rhamnosus and L. paracasei showed the highest production of benzoic acid. Therefore, the use of L. rhamnosus, L. paracasei, S. thermophilus, and different incubation temperatures were examined to optimize benzoic acid production. Response surface methodology (RSM) based on a central composite design was performed for various incubation temperatures (35-44℃) and starter culture inoculum ratios (0-0.04%) in a commercial range of dairy fermentation processes. The optimum conditions were 0.04% L. rhamnosus, 0.01% L. paracasei, 0.02% S. thermophilus, and 38.12℃, and the predicted and estimated concentrations of benzoic acid were 13.31 and 13.94 mg/kg, respectively. These conditions maximized naturally occurring benzoic acid production during the yogurt fermentation process, and the observed production levels satisfied regulatory guidelines for benzoic acid in dairy products.

• Food Science and Biotechnology
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• v.17 no.2
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• pp.379-383
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• 2008

Extraction characteristics of garlic and functional properties of corresponding extract were monitored by response surface methodology (RSM). Maximum extraction yield of 26.41% was obtained at microwave power of 146.29 W, ethanol concentration of 63.31 %, and extraction time of 5.88 min. At microwave power, ethanol concentration, and extraction time of 114.84 W, 58.83%, and 1.42 min, respectively, maximum electron-donating ability (EDA) was 72.86%. Maximum nitrite-scavenging ability was 94.62% at microwave power, ethanol concentration, and extraction time of 81.83 W, 2.65%, and 3.83 min, respectively. Superoxide dismutase (SOD) showed maximum pseudo-activity of 49.12% at microwave power of 34.23 W, ethanol concentration of 33.11 %, and extraction time of 4.40 min. Based on superimposition of 4-dimensional RSM with respect to extraction yield, electron-donating ability, nitrite-scavenging ability, and pseudo-activity of SOD, optimum ranges of extraction conditions were microwave power of 0-100 W, ethanol concentration of 40-70%, and extraction time of 2-8 min.

• Journal of the East Asian Society of Dietary Life
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• v.19 no.1
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• pp.38-44
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• 2009

The principal objective of this study was to determine the optimal mixing ratios of three different quantities of spirulina, salt and water for the preparation of Korean rice cake (Dukbokiduk) via response surface methodology on the basis of color, texture, and sensory test. The spirulina levels were tested in a range of $1{\sim}3%$, the water levels in a range of $15{\sim}25%$, and salt levels were tested a range of $0.5{\sim}1%$ by weight of rice powder. Taste was influenced most profoundly by the amount of added spirulina. Optimal taste was achieved with 1% of spirulina, 0.75% of salt and 20% water. Thus, the optimal mixing ratios of spirulina, salt, and water for Dukbokiduk were 1.0%, 0.57%, and 19.46%, respectively.

• Proceedings of the Korean Nutrition Society Conference
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• 1992.05a
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• pp.23-23
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• 1992

• Preventive Nutrition and Food Science
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• v.13 no.4
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• pp.334-339
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• 2008

This study was designed to determine the optimum conditions of heating temperature, heating time and dilution rates for producing heated garlic juice by using central composite design of response surface methodology. Garlic 3Department of Biosystems Engineering, Chungbuk National University, Cheongju 361-763, Korea was heated using a high temperature and pressure treatment apparatus. Total soluble solid contents ranged from 4.4 at $130^{\circ}C$ 3 hr and 6 fold dilution to 5.89 at $115^{\circ}C$ for 2 hr and 8 fold dilution. The highest total acidity was 0.55% at $120^{\circ}C$ for 3 hr and 2 fold dilution. The pH ranged from 4.01 at $130^{\circ}C$, 3 hr and 6 fold dilution to 5.85 at $120^{\circ}C$, 1 hr and 6 fold dilution. From the results of statistical analysis on the sensory evaluation the predicted optimum processing conditions for best color, taste, flavor and overall acceptance were $119.41^{\circ}C$, 3.11 hr, 5.85 fold dilution, $118.23^{\circ}C$, 3.57 hr, 3.15 fold dilution, $120.54^{\circ}C$, 3.47 hr, 5.01 fold dilution and $119.54^{\circ}C$, 3.18 hr, 5.66 fold dilution, respectively. The application of response surface methodology for preparing heated garlic juice processing showed a good correlation with high significance.

• Food Science and Industry
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• v.54 no.1
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• pp.29-33
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• 2021

Particulate matter (PM) is an air pollutant that causes serious environmental problems in Korea and other countries. The annual average PM10 concentration in Korea is around 40 ㎛/㎥, which is more than twice as high as the WHO recommended standard. When consumed with food, fine PM can pose a risk to humans. However, the risk of fine PM has been focused on the risk of fine PM introduced through the respiratory system. We investigated the quantitative measuring methods of PM10 on food surface to identify possible risk analysis of fine PM. The surfaces of food with artificially contaminated PM10 were observed with a scanning electron microscope(SEM). An automatic object-based image analysis was used to analyze the amount and size distribution of particulate matter contained in SEM micrographs.

• Journal of the Korean Applied Science and Technology
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• v.33 no.1
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• pp.155-167
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• 2016

Surface-active substances in defatted rapeseed cake were obtained using a supercritical fluid extraction method. Then, it was purified by removing sinapine in the extract through a series of steps using a mixed solvent: diethyl ether and ethyl acetate (1:1, v/v). Emulsifying properties of purified surface-active substances were investigated, including fat globule size, zeta potentials and creaming stability and its antioxidant activity in emulsion systems were also studied by peroxide value and $^1H$-NMR spectrum. It was found that fat globules in emulsions with purified surface-active substances were much smaller than ones with the unpurified. In addition, as pH of the emulsion lowered and with increasing NaCl concentration in the emulsion, they were observed to increase, which led to worse creaming stability. These properties were reflected in changes of zeta potentials of emulsions. The oxidative stability was better in emulsions with purified surface-active substances than ones with Tween 20 or commercial lecithin, possibly resulted from the existence of sinapic acid in the extract. It was concluded that purified surface-active substances from defatted rapeseed cake could be simultaneously used as emulsifier and antioxidant agent in emulsion system.

• Korean journal of food and cookery science
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• v.23 no.1 s.97
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• pp.1-8
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• 2007

Extraction conditions were optimized using response surface methodology for preparing high-quality, hot water extracts from cultivated Chrysanthemum indicum L. petals. A fractional factorial design was applied to investigate the effects of added sample ratio ($X_1$), extraction temperature ($X_2$) and extraction time ($X_3$) variables on extract properties, such as, soluble solid contents ($Y_1$), sugar content ($Y_2$), ?E ($Y_3$), turbidity ($Y_4$), total phenol ($Y_5$) and DPPH ($Y_6$). Second-order models were employed to generate a 3-dimensional response surface for dependent variables and their coefficients of determination ($R^2$) ranged from 0.8408${\sim}$0.9914. The range of optimum conditions at $80^{\circ}C$ extraction for maximize characteristics of hot water extracts was 2.3${\sim}$2.7 g and 9.2${\sim}$11.2 hr.

• Food Science and Biotechnology
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• v.18 no.4
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• pp.867-871
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• 2009

Response surface methodology (RSM) was used for the optimization of antioxidant capacity in gardenia extracts. The antioxidant capacities of gardenia fruit extracts were investigated by ferric reducing ability (FRA) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity (RSA) assays. The optimum extraction parameters for the strongest antioxidant capacity were the ethanol concentration (EtOH) of 48.9%, extraction temperature of $72.9^{\circ}C$, and extraction time of 29.9 min. Analysis of variance (ANOVA) showed that the quadratics of EtOH and extraction temperature had highly significant effect on the antioxidant capacity (p<0.001). The antioxidant capacity was correlated with contents of bioactive components [crocin, geniposide, and total phenolic (TP) compounds] in gardenia extracts and mainly attributed to the content of the TP compounds.