• Korean Journal of Food Science and Technology
• /
• v.21 no.2
• /
• pp.203-211
• /
• 1989

During hot air drying of root vegetables such as radish and sweet potatoes, shrinkage and casehardening occurred, and thereby the quality change appeared. Therfore the hot air drying apparatus in which air temperature, relative humidity and air velocity could be controlled was designed, and the drying and shrinking characteristics of radish and sweet potatoes were studied. Also the external factors that affected these characteristics were investigated. The whole drying process of radish and sweet potatoes could be divided into four different drying rate periods, namely constant rate period, first falling rate period, second falling rate period (a) and (b). The shrinking rate curve consisted of four periods nearly corresponding to drying rate periods. The shrinking rate slowly increased in the constant rate period, rapidly increased in the first falling rate period, and reached the highest value in the early period of the second falling rate period. The surface shrinkage was greatly affected by the thickness of sample, relative humidity and initial moisture content. The shrinking ratio was increased with decreasing thickness and increasing relative humidity and initial moisture content.

• Korean Journal of Food Science and Technology
• /
• v.21 no.2
• /
• pp.212-217
• /
• 1989

The shrinking and overall drying rate equations which can accomodate experimental date and the rate of initial drying ratio were investigated. The results obtained from hot air drying experiments of radish and sweet potatoes were as follow. The drying rate constant and the order were affected by the thickness of sample and temperature. The empirical drying rate and shrinking equations at constant drying conditions (d=4mm, $Ta=50^{\circ}C$, RH=10%, U=0.8m/s) for radish and sweet potatoes were found to $dx/dt=0.112{\times}10^{-2}\;A(1-x)^{0.43}$, A=Ao(-0.480x+1) and rates of initial drying ratio were expressed of sample thickness, relative humidity and air velocity; for radish $dx/dt=0.0648(RH)^{-0.31}\;(d)^{-0.75}\;(U)^{0.39}$ and for sweet potatoes $dx/dt=0.0547(RH)^{-0.28}\;(d)^{-0.63}\;(U)^{0.37}$

• The Korean Journal of Food And Nutrition
• /
• v.34 no.4
• /
• pp.356-364
• /
• 2021

This study was carried out to investigate the effects of supercritical carbon dioxide (SC-CO₂) extracts from sweet potatoes (SP) and watermelon (WM) on the oxidative stability of perilla seed oils (POs) over the existing ones. A comparison was done between the oxidative stability of perilla oil (PO) after the addition of 0.1% of SP, and WM extracts and PO without extract. The oxidative stability was measured based on the viscosity, acid value (AV), peroxide value (POV), antioxidant (DPPH) activity, p-anisidine value (p-AV), and fatty acid composition. The viscosities ranges were: PO without extract, from 53.99±0.99 to 74.38±1.61 cps, PO with SP extract, from 53.99±0.10 to 58.73±0.8 cps, and PO with WM extract, from 53.98±0.10 to 56.00±0.70 cps. While the PO containing the SC-CO₂ extracts had significantly lower AV, POV, and p-AV, their antioxidant activity was approximately 10 times higher than that of the PO without extract. There were no significant differences in fatty acid composition between SC-CO₂ extracts added groups and PO without extract (p<0.05). The findings of this study confirmed that the SC-CO₂ extracts from sweet potatoes and watermelon enhanced the oxidative stability of perilla seed oils, and are potential natural antioxidants for use in the food industry.

• The Korean Journal of Food And Nutrition
• /
• v.31 no.2
• /
• pp.264-271
• /
• 2018

The objective of this study was to investigate taste profiles and the correlation of Doenjang soup solution prepared with three different temperatures (5, 25, $45^{\circ}C$) and using an electronic nose (e-nose), electronic tongue (e-tongue), and descriptive analyses by trained panelists. A total of 17sensory attributes were generated from the descriptive analyses for the Doenjang soup solution. There were significant difference among the samples in the cooked soybean flavor, the cooked soybean odor, the soy sauce odor, the sweet odor, the sweet taste, and the sweet aftertaste attributes. The intensities of these sensory attributes tended to increase as the serving temperature of the Doenjang soup solution increased. There were seven volatile compounds detected by the electronic nose: ethanol, propanal, 2-methylpropanal, ethyl acetate, 3-methylbutanal, and beta-pinene. The intensities of the volatile compounds increased as the temperature of the Doenjang soup solution increased. On the other hand, the intensities of the basic tastes by the e-tongue decreased as the temperature of the Doenjang soup solution increased. In conclusion, the e-nose, e-tongue, and descriptive analysis results showed different correlations depending on the temperature of the Doenjang soup solutions.

• The Plant Pathology Journal
• /
• v.31 no.4
• /
• pp.388-401
• /
• 2015

Sweet potatoes (Ipomea batatas L.) are grown extensively, in tropical and temperate regions, and are important food crops worldwide. In Korea, potyviruses, including Sweet potato feathery mottle virus (SPFMV), Sweet potato virus C (SPVC), Sweet potato virus G (SPVG), Sweet potato virus 2 (SPV2), and Sweet potato latent virus (SPLV), have been detected in sweet potato fields at a high (~95%) incidence. In the present work, complete genome sequences of 18 isolates, representing the five potyviruses mentioned above, were compared with previously reported genome sequences. The complete genomes consisted of 10,081 to 10,830 nucleotides, excluding the poly-A tails. Their genomic organizations were typical of the Potyvirus genus, including one target open reading frame coding for a putative polyprotein. Based on phylogenetic analyses and sequence comparisons, the Korean SPFMV isolates belonged to the strains RC and O with >98% nucleotide sequence identity. Korean SPVC isolates had 99% identity to the Japanese isolate SPVC-Bungo and 70% identity to the SPFMV isolates. The Korean SPVG isolates showed 99% identity to the three previously reported SPVG isolates. Korean SPV2 isolates had 97% identity to the SPV2 GWB-2 isolate from the USA. Korean SPLV isolates had a relatively low (88%) nucleotide sequence identity with the Taiwanese SPLV-TW isolates, and they were phylogenetically distantly related to SPFMV isolates. Recombination analysis revealed that possible recombination events occurred in the P1, HC-Pro and NIa-NIb regions of SPFMV and SPLV isolates and these regions were identified as hotspots for recombination in the sweet potato potyviruses.

• The Korean Journal of Pesticide Science
• /
• v.16 no.3
• /
• pp.236-241
• /
• 2012

The characteristics of chlorpyrifos was studied to clarify the effect of the cultivation season, spray intervals, spray volume and concentration on residues in chilli and sweet peppers cultivated under greenhouse condition. Residue levels of chlorpyrifos detected in chilli pepper fruit cultivated were 1.5 to 2.7 times higher in winter(February-March) than those in summer(June-July). During winter season residue levels of chlorpyrifos in chilli peppers were 6.9~3.2 times higher than those in sweet peppers for 10 days after 3 times application with 7 days interval. Residue levels in chilli pepper were from 2.070 mg/kg at 1 day to 0.929 mg/kg at 10 day, while those in sweet pepper were from 0.302 mg/kg to 0.291 mg/kg. Residue levels in sweet pepper to which are 3 times applied with 7 days interval were from 0.302 mg/kg at 1 day to 0.291 mg/kg at 7 day, and the residue levels in sweet pepper which are 3 times applied with 3 days interval were from 0.498 mg/kg at 1 day to 0.470 mg/kg at 7 day. Residue levels of chlorpyrifos in the sweet peppers applied by double concentration were 2.5 times higher than those sprayed by normal standard amounts diluted in double volume.

• Food Science and Preservation
• /
• v.7 no.3
• /
• pp.331-336
• /
• 2000

The phenolic compounds of Korean sweet potatoes, Mokpo 18 and Yulmi, were extracted by using 70%-methanol and the extracts(ME) were fractionated and obtained three fractions such as free phenolic acid(FPAF), soluble phenolic acid ester(SPAF) and insoluble bound phenolic acid(BPAF) fractions. The antioxidative activities(AA) was represented as the peroxide values(POVs). The POVs were calculated by measuring the oxidation of linoleic acid and lard emulsions at $60^{\circ}C$. AA of FPAF has shown the most effective. AA of FPAF were more effective than those of ME in both Yulmi and Mokpo 18. AA of the ME of Mokpo 18 were more effective than those of Yulmi, however, those of FPAF in Ulmi were more effective than in Mokpo 18. The POVs of ME and FPAF of the peel part in both sweet potatoes were more effective than those of peeled part. The qualitative and quantitative analysis of the phenolic compounds in both sweet-potatoes were performed by using high performance liquid chromatography(HPLC) and the major phenolic compounds were identified as chlorogenic acid and caffeic acid. The contents of caffeic acid were 0.684mg/g in the peel part and 0.028mg/g in the peeled part of Yulmi and 0.472mg/g in the peel part and 0.046mg/g in the peeled part of Mokpo 18 and those of chlorogenic acid was 0.674mg/g, 0.926mg/g, and 0.012mg/g, respectively. In comparative test of antioxidative activities between a standard chlorogenic acid and caffeic acid, AA of caffeic acid were more effective than those of chlorogenic acid.

• Journal of Plant Biotechnology
• /
• v.43 no.4
• /
• pp.397-404
• /
• 2016

Sweet and taste modifying proteins are natural alternatives to synthetic sweeteners and flavor enhancers, and have been used for centuries in different countries. Use of these proteins is limited due to less stability and availability. However, recent advances in biotechnology have enhanced their availability. These include production of sweet and taste modifying proteins in transgenic organisms, and protein engineering to improve their stability. Their increased availability in the food, beverage or medicinal industries as sweeteners and flavor enhancers will reduce the dependence on artificial alternatives. Production of transgenic plants using sweet and taste modifying genes, is an interesting alternative to the extraction of these products from natural source. In this review paper, we briefly describe various sweet and taste modifying proteins (such as thaumatin, monellin, brazzein, curculin and miraculin), their properties, and their application for plant development using biotechnological approaches.

• The Plant Pathology Journal
• /
• v.31 no.1
• /
• pp.41-49
• /
• 2015

Sweet cherry is an important fruit crop with increasing economical value in Turkey and the world. A number of viruses cause diseases and economical losses in sweet cherry. Prune dwarf virus (PDV), is one of the most common viruses of stone fruits including sweet cherry in the world. In this study, PDV was detected from 316 of 521 sweet cherry samples collected from 142 orchards in 10 districts of Isparta province of Turkey by double antibody sandwich-enzyme linked immunosorbent assay (DAS-ELISA). The presence of PDV in ELISA positive samples was confirmed in 37 isolates by reverse transcription- polymerase chain reaction (RT-PCR) method. A genomic region of 862 bp containing the coat protein (CP) gene of PDV was re-amplified from 21 selected isolates by RT-PCR. Amplified DNA fragments of these isolates were purified and sequenced for molecular characterization and determining genetic diversity of PDV. Sequence comparisons showed 84-99% to 81-100% sequence identity at nucleotide and amino acid level, respectively, of the CP genes of PDV isolates from Isparta and other parts of the world. Phylogenetic analyses of the CP genes of PDV isolates from different geographical origins and diverse hosts revealed that PDV isolates formed different phylogenetic groups. While isolates were not grouped solely based on their geographical origins or hosts, some association between phylogenetic groups and geographical origins or hosts were observed.

• Preventive Nutrition and Food Science
• /
• v.14 no.1
• /
• pp.60-65
• /
• 2009

Cookies were prepared by adding different levels (0, 5, 10, 15, and 20%) of purple sweet potato powder (PSPP) and their physicochemical and sensory characteristics were examined. With increase of the PSPP level, moisture content decreased and ash content increased (p<0.05). The spread factor of control cookies was higher than that of cookies containing PSPP. The incorporation of PSPP in cookies lowered the lightness and yellowness but increased redness (p<0.05). Texture measurement showed that the addition of PSPP did not affect the hardness of cookies. Results of acceptance test revealed that overall acceptability score was not significantly different between the control and the PSPP added cookies. Therefore, it is suggested that PSPP can be incorporated into cookies up to 20% without affecting the cookie quality. Total polyphenol content and antioxidant activity were assessed to examine the functionality of cookies. In addition, substitution of wheat flour with PSPP yielded cookies with higher polyphenol content and antioxidative activity (p<0.05). The peroxide value (POV) and acid value increased during storage at $60^{\circ}C$ for 80 days. The POV was significantly lower in cookies containing PSPP than the control cookies, suggesting that the addition of PSPP deterred the lipid oxidation (p<0.05).