• Horticultural Science & Technology
• /
• v.32 no.5
• /
• pp.636-644
• /
• 2014

This experiment examined the effects of preharvest Ca-chitosan spraying and short-term post-harvest treatment with high $pCO_2$ on the shelf-life of 'Seolhyang' strawberry fruit. Fruit firmness decreased when harvested late in the season and was little affected by Ca-chitosan spray treatments. Short-term treatment with high $pCO_2$ after harvest, however, significantly increased fruit firmness regardless of preharvest treatment. The combined treatment of Ca-chitosan spray and high $pCO_2$ led to an additional increase in shelf-life through delay of skin disorder, fruit decay incidence and firmness loss during simulated marketing. The residual effects of both treatments, however, were reduced when fruit were harvested late in the season. Fruit firmness was more affected by high $pCO_2$ treatment whereas decay and visual quality were affected by preharvest spraying with Ca-chitosan. Although more research is required to determine the optimum concentration of calcium and chitosan, and the optimal spray interval, our results show that the combined treatment of preharvest Ca-chitosan spray and postharvest high $pCO_2$ is effective in improving strawberry fruit shelf-life by increasing firmness and delaying decay.

• Korean journal of food and cookery science
• /
• v.17 no.4
• /
• pp.316-322
• /
• 2001

The effect of onions on the quality characteristics of strawberry jam substituted with 50% fructo-oligosaccharide for sucrose was investigated. Strawberry jams with 10, 20, 30 and 40% onions in place of strawberry were prepared and evaluated for moisture content, pH, total acidity, color, spreadability, soluble solid content, reducing sugar, residual anthocyanin, instrumental texture and sensory characteristics. As the amount of onions increased, moisture content, total aridity, spreadability, soluble solid content, reducing sugar content and residual anthocyanin content of strawberry jams decreased, while pH increased. The lightness and redness decreased with addition of onions, but the yellowness increased. The sensory scores for strawberry jams decreased with the increase of onion content; however, strawberry jams with 10 or 20% onions showed fairly good scores.

• Korean Journal of Food Science and Technology
• /
• v.35 no.5
• /
• pp.849-855
• /
• 2003

The extrusion effects on solubilization of brown rice, glutinous rice, barley and job's tear were investigated in comparison with raw and roasted whole grains. Whole grains were extruded under 13 different operating conditions, where the process variables were controlled in the following ranges: screw speed, $200{\sim}300$ rpm; temperature, $110{\sim}130^{\circ}C$; moisture, $15{\sim}25%$. Solubilization effects of whole grains by extrusion were characterized in terms of water solubility index (WSI), viscosity, dispersibility and dietary fiber in comparison with those of raw and roasted grains. WSI of whole grains significantly increased by extrusion, especially WSI of glutinous rice containing abundant amylopectin increased twice than WSI of brown rice. The content of soluble dietary fiber was increased due to extrusion treatment, while insoluble dietary fiber decreased concomitantly and the content of total dietary fiber was not nearly changed. Extrusion improved the dispersibility and swelling effects in comparison with that of raw and roasting grains.

• Korean Journal of Food Science and Technology
• /
• v.20 no.4
• /
• pp.504-510
• /
• 1988

The physicochemical properties of rice flours which were obtained by dry milling(blade, hammer, test and micro mill) and wet & dry milling (roller & micro mill) were investigated. The resulting flour particle sizes were reduced in the order that of blade, hammer, test, micro and roller & micro mill. Scanning electron microscopic examination showed that the starch granules were freed from the imbedding matrix as the particles became finer. The test-milled flour had the hightest levels of starch damage, maltose value and hot-water soluble amylose content, and the blade-milled flour showed the lowest levels. Amylograph viscosity and gelatinization temperature of the flours decreased as the particles became finer, and the addition of $Hg^{+2}$ increased the peak viscosity of the dry-milled flour pastes, whereas the wet & dry-milled flour did not show any changes. The blue values and ${\lambda}$max values of the iodine complex of the cold-water extractable ${\alpha}-D-glucan$ from flours were in the range of 0.023-0.029 and 518-522nm, respectively, indicating these materials were shown to be mainly composed of amylopectin-like polymer.

• Food Science and Preservation
• /
• v.24 no.7
• /
• pp.934-941
• /
• 2017

The objective of this study was to investigate the effect of corrugated packaging coated with aluminum (Al) on quality characteristics of red paprika during storage at $25^{\circ}C$. Characteristics such as weight loss, hardness, total phenolic content, antioxidant activities, polygalacturonic acid (PG) activity, and oxidative enzyme activities (polyphenol oxidase and peroxidase activities) of paprikas, packed in corrugated packaging with or without Al-coating were compared as a function of storage time. Al coating inside of corrugated box was found to inhibit PG activity, resulting in prevention of weight loss and maintenance of hardness of paprika during storage, compared to the control sample. This may be due to Al coating treatment that enhance moisture-proof property and hinder gas transmission of corrugated packaging. Furthermore, paprika in Al-coated-corrugated packaging was lower in oxidative enzyme activities than the control, which caused higher total phenolic content and antioxidant activities during storage. As a results, the Al coated-corrugated packaging can be used as a functional packaging material to extend the shelf-life and improve the storage quality of paprika by preventing their respiration and transpiration.

• Journal of the East Asian Society of Dietary Life
• /
• v.25 no.4
• /
• pp.660-666
• /
• 2015

Natural food colorant are widely used to satisfy consumer preferences. Anthocyanins are red, blue and purple natural pigments. Purple-fleshed sweet potato (PSP) contains large quantities of anthocyanins. The aims of this work were i) to investigate the influence of sugars on the purple color of PSP jam and ii) to optimize the ratio of ingredients for sensory characteristics of PSP jam. Korean PSP variety "Sinjami" was used for the preparation of jam. The jams were prepared with various sugar contents (0, 20, 30, 40 and 50% total weight) consisting of steamed purple-fleshed sweet potato, water, lemon juice and apple juice. With increasing sugar contents, lightness (L) and redness (a) of PSP jams decreased while yellowness (b) increased, indicating that anthocyanins were degraded and/or brown pigments were formed due to high sugar content under heat treatment. Hardness, springiness, chewiness and cohesiveness showed significant differences among PSP jams with various sugar contents. In sensory evaluation, addition of sugar significantly increased scores for color and texture as compared to control samples. The color, texture and preference results indicate an optimal sugar content of 40% total ingredient weight for PSP jam.

• The Korean Journal of Mycology
• /
• v.21 no.2
• /
• pp.106-111
• /
• 1993

Pectolytic enzymes were extracted in apple fruits rotted by Botryosphaeria dothidea, and their activities and change of pectic substances were investigated. Exo-polygalacturonase(exo-PG), exo-polymethylgalacturonase(exe-PMG), polygalacturonate-trans-eliminase(PGTE) and pectin-methyl-trans-eliminase(PMTE) were produced by the pathogen. Activities of exo-PG and exe-PMG extracted from rotten apple fruits were high to 21.15 and 24.65 units/mg protein in specific activity at seven days after inoculation, respectively. Activities of PGTE and PMTE showed 5.60 and 7.90 units/mg protein, respectively, but they were lower than those of the exo-type enzymes. Water-soluble and versene-soluble pectins were 11.50 mg/100 mg-AIS and 7.31 mg/100 mg-AIS at 14 days after inoculation, namely, they were increased by 4.23 and 2.16 mg/100 mg-AIS over those of sound apples, respectively. Total soluble pectic substances of rotten apple were 72.4% of total pectic substances and it was higher by 24.8% than sound apple. Insoluble pectic substance was notably decreased from 15.32 to 7.16 mg/100 mg-AIS according to progress of decay while total pectic substances were not changed remarkably.

• Korean Journal of Food Science and Technology
• /
• v.27 no.4
• /
• pp.625-630
• /
• 1995

In order to know the effects of hot-water extracts of starches on gel formation and gel properties, some physicochemical properties and molecular distribution of the extracts were measured. Also, after acid-hydrolysis of starch gels and extract gels, extent of hydrolysis and $\overline{D.P}._n$, and molecular distribution of hydrolysis-residue were measured. Extraction ratio of grain starches (buckwheat, corn, rice, and wheat) were $4.0{\sim}6.6%$. The ratio of acorn and mungbean starches were 11.7 and 13.5%, respectively. Iodine affinity of the extracts was $17.2{\sim}17.7%$ in starches using for Mook, SM(acorn, buckwheat, and mungbean), $13.7{\sim}14.9%$ in starches not using for Mook, SNM(corn, rice, and wheat). Blue value was also higher in SM than in SNM. $\overline{D.P}._n$. of extracts of SM were bigger than those of SNM. In molecular distribution experiment, amylopectin fraction was not found from the extracts except rice starch extract. The extent of acid hydrolysis of the starch gels were $70{\sim}84%$ after 60 days, and the extent of the extract gels were $22{\sim}35%$. The extent of hydrolysis of starch gels and extract gels made with SM were lower than those of SNM.

• Korean Journal of Food Science and Technology
• /
• v.33 no.2
• /
• pp.161-165
• /
• 2001

The dietary fiber was extracted from apple pomace with various concentrations of acidic, alkaline solvents and water in $24.4{\sim}29.3%$ yield. The extractions of water-soluble dietary fiber with acidic(6.85%) and alkaline solvent(6.55%) were more effective than the water extraction(6.0%). The higher extraction yield was obtained with increased concentration of acidic or alkaline solvents. The content of galacturonic acid was higher in the order, 0.01 M HCl(77.5%)>0.05 M HCl(76.8%)>$H_2O(76.1%)$>0.05 M NaOH(73.8%)> 0.01 M NaOH(69.0%) and the extraction with acidic solvent showed the highest pectin yield. The color value increased by extraction with solvent in higher concentration. And at equal concentration, the color value of alkaline extract was higher than that of acidic exctract. There was no relationship between the color value and the extraction yield of dietary fiber. In the investigation on the rheological properties, the shear stress increased in proportion to galacturonic acid contents. While water-soluble dietary fiber extracted with acid and water represented Newtonian rheological properties, the alkaline extract was inclined to have converting property from pseudoplastic to Bingham pseudoplastic with increment of alkaline concentration. In the studies on the time-dependence of apparent viscosity, the thixotropic property with hysteresis loop was observed in alkaline extract.

• Korean Journal of Food Science and Technology
• /
• v.28 no.2
• /
• pp.371-377
• /
• 1996

Potential health promoting effects such as antiallergic, anti-inflammatory, antiviral, anticancer and anticarcinogenic properties have been ascribed to citrus flavonoids. Dietary fibers have also been used as functional food components due to the various beneficial physiological activities. Two kinds of flavonoids, naringin and hesperidin, were identified both in the pulp and in the peel of Korean tangerine. The contents of naringin and hesperidin in the pulp were 2.95 mg/100 g and 0.53 mg/100 g, respectively. However, the contents of naringin and hesperidin in the peel were much higher (10.77 mg/100 g and 38.90 mg/100 g) thanthose of two identified flavonoids in the pulp. The content of soluble dietary fiber (SDF) in the pulp of tangerine was 1.90%, insoluble dietary fiber (IDF) 0.37%, and total dietary fiber (TDF) 2.27% based on wet matter, respectively. The content of SDF was 1.09%, IDF 4.77% and TDF 1.86% in the peel of tangerine. The total pectin content was 1.53% in the pulp and 0.94% in the peel of tangerine. The peel of Korean tangerine, a by product in tangerine processing, would be a good source for the production of naringin, hesperidin and pectin.