• Journal of the East Asian Society of Dietary Life
• /
• v.23 no.5
• /
• pp.637-644
• /
• 2013

This study was conducted to obtain the baseline data for fermented tea with King oyster (Pleurotus eryngii) mushroom mycelium as well as to investigate the possibility of development for deodeok processing products. For this research, the physicochemical properties and antioxidant activity for fermented tea were confirmed by different roasting temperatures and roasting times. The results of the physicochemical properties, browning, turbidity, reducing sugar, total polyphenol and total flavonoid contents, were increased with increasing roasting temperature and roasting time, whereas the pH was decreased. The results of the antioxidant activity test of fermented tea, DPPH radical-scavenging activity, FRAP and reducing power, were increased with increasing roasting temperature and roasting time. The preference of fermented tea was confirmed as being the highest when roasted at $180^{\circ}C$ for 30 min. Although fermented tea did not have a unique flavor of mushroom and burnt flavor, it had strong color, flavor and taste. For this reason, fermented tea production for high content of functional materials and high preference is possible by roasting at $180^{\circ}C$ for 30 min. As for the results of this study, the physical properties of fermented deodeok were relatively stable on high temperature exposure and furthermore, the development of a variety of foods will be possible because fermented deodeok has an antioxidant capacity.

• Korean Journal of Food Science and Technology
• /
• v.30 no.6
• /
• pp.1279-1284
• /
• 1998

This study was designed to investigate the reasonable roasting condition of chicory. Extraction and surface color development of roasted chicory were significantly influenced by roasting temperature and time, and they were increased with increasing time, and roasting at $170^{\circ}C$ showed the highest browning color development. Soluble solid contents was not affected by roasting temperature and time. Roasting for 10min at $150^{\circ}C$ exhibited the highest sensory score, at which the free sugar composition of the extract was 0.87% xylose, 0.62% fructose and 0.84% sucrose. A total of 17 volatile components were identified by GC/MSD from the dried and roasted chicories. Aldehyde, ketone and pyrazine compounds were found to be major volatile flavor components in chicory roots. It was concluded that the results of this work will be useful to determine the optimum conditions for roasting of chicory roots.

• Korean Journal of Food Science and Technology
• /
• v.28 no.2
• /
• pp.246-252
• /
• 1996

Changes in physicochemical properties of the defatted sesame meals at various roasting temperature and time have been studied. The roasting temperatures were $190^{\circ}C,\;210^{\circ}C,\;and\;230^{\circ}C,$ whereas roasting times were 5, 10, 20 and 30 minutes, The protein content of defatted sesame meals decreased during roasting and the oil content of the meals roasted at$210^{\circ}C$ for 10 minutes was 8.4%. The yields of sesame mea]s and oil, when roasted at $210^{\circ}C$ for 10 minutes, were 50.1% and 46.9%, respectively. The amino acids in sesame meals gradually decreased as roasting conditions became severe. Sucrose (162.6 mg%), glucose (37.7 mg%) and fructose (18.7 mg%) were detected in the raw sesame meals. The color of roasted sesame seeds and oils extracted from them became darker as the roasting temperature and time increased and the change in lightness greatly affected the total color change. The browning pigment of the sesame meal roasted at $190^{\circ}C$ was separated into a fraction I, II and III. When roasted at $230^{\circ}C$ for longer than 10 minutes, the soluble browning pigment decreased.

• Korean Journal of Food Science and Technology
• /
• v.50 no.1
• /
• pp.111-116
• /
• 2018

Roasting process of grains modifies their physicochemical characteristics that affect flavor, color, taste, and textures, as well as composition of bioactive compounds. We roasted oats at different temperatures (150, 200, and $250^{\circ}C$) and for different time periods (15 and 30 min). The polyphenol and flavonoid contents in different solvent extracts (methanol, fermented ethanol, and water) were also investigated. The total polyphenol and flavonoid contents were highest in the methanolic extract (135 mg gallic acid equivalent/g and 29 mg catechin equivalent/g, respectively, at $250^{\circ}C/30min$ roasting) and increased with roasting time and temperature. In addition, the avenanthramides were most abundant as accessed ($266{\mu}g/g$) in the methanolic extract upon roasting at $200^{\circ}C$ for 15 min. The radical scavenging activities, using 2,2-diphenyl-1-picrylhydrazyl and 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid scavenging, increased with roasting temperature and time. The roasting process may modify the physicochemical structure of oats, thereby, improving polyphenol extraction and antioxidant activity. The results of this study could be used for the manufacture of foods using roasted oats.

• Food Science and Preservation
• /
• v.12 no.2
• /
• pp.146-150
• /
• 2005

A comparative study of pretreatment and extraction methods was conducted to investigate their effects on nutritional and bioactive components during hot-water extraction of Acanthopanax senticosus. The herb samples, ground and sifted $(8\~20\;mesh)$ were pretreated with ultrasound (20 kHz), microwave (2,450 MHz) or roasting $(180^{\circ}C)$ for 10 min, and then extracted by a boiling $(180^{\circ}C)$ under atmospheric pressure or a pressured boiling $(121^{\circ}C)$ for 2 hr. In general, the pretreatments improved the extraction efficiency and the DPPH radical scavenging activity of extract. Particularly, the extraction yields of soluble solids, total sugar and phenolic compounds were increased in microwaving methods, and the protein yield and the radical scavenging activity were higher in roosting pretreatment. Yields of soluble solids, total sugar, protein and phenolic compouds in pressured extraction were higher than those in nonpressured extraction. These results suggested that pretreatment including microwave radiation, sonication and roasting and pressured extraction can be utilized for improving the extraction efficiency of A. senticosus.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.43 no.12
• /
• pp.1881-1888
• /
• 2014

Pre-thermal treatment is important to minimize quality changes during main cooking or storage. In this study, to optimize pre-thermal treatment of carrots, three types of pre-thermal treatments were applied to carrots and quality changes such as physicochemical, nutritional, or sensory properties were observed. Washed and sliced carrots were thermally treated by hot-water immersion ($100^{\circ}C$, 1~10 min), steaming ($100^{\circ}C$, 1~10 min), and stir-frying with oil (10~80 sec). Carrot tissue was maintained until 2 min hot-water immersion or steaming, and they were damaged by just 30 sec of stir-frying. Color and hardness were significantly affected by treatment time and temperature. Color was completely changed after 5 min and 7 min by hot-water and steam treatments, respectively. Hardness decreased to 44% compared with fresh carrot (4,500 g) after 1 min, 3 min, and 20 sec of hot-water, steam, and stir-frying, respectively. For nutritional changes, ascorbic acid, organic acid, and peroxide activity were reduced by all treatments compared with fresh carrot. Especially, succinic acid was dramatically reduced by hot-water treatment. Otherwise, free sugar contents were increased with greater treatment time in all samples. In this study, pre-thermal treatment of carrot was optimal at 2 min steaming treatment.

• Korean Journal of Plant Resources
• /
• v.35 no.4
• /
• pp.455-463
• /
• 2022

The effects of freeze-drying (FD), room-temperature drying (RD), and room-temperature drying after roasting (RDAR) on the volatile organic compounds (VOCs), sugar content, flavonoids, and antioxidant activity of Hallabong peel tea were tested. This experiment was conducted to collect a basic information for developing of peel tea. FD samples showed lower total soluble solids and VOCs than other drying treatments. RDAR samples showed a significant difference in VOCs and visual color of FD samples. The reduced VOCs in FD samples was caused by freeze drying treatment; identical VOCs composition of hallabong peel was detected from condensed ice of freeze-drying machine. Metabolomics analysis showed no difference among three drying treatments. In addition, antioxidant activity and total phenolic compounds were not significantly different from three different drying treatments. Thus, RD or RDAR is a suitable drying method for hallabong peel tea rather than FD method in terms of VOCs and economical reasons.

• Korean journal of food and cookery science
• /
• v.11 no.1
• /
• pp.44-50
• /
• 1995

In order to investigate the mechanical and sensory characteristics of dried Lentinus edodes, raw Lentinus edodes, Pleurotus ostreatus and Agaricus bisporus by various cooking methods, texture measurements and sensory evaluation were performed. And the results were summarised as follows. Hardness, cohesiveness, springiness, gumminess and chewiness of those mushrooms, except the cohesiveness and springiness of Pleurotus ostreatus head, showed significant differences depending on the cooking methods. Microwave heating of mushrooms, in general, give high values in mechanical characteristics measurements. As a results of sensory evaluation, salt water blanching turned out to be the most preferred cooking method among blanching, steaming, microwave heating. The mushroom dishes were preferred by the panel in the order of Jungol, Hoi, Fritter, Saute and Jun.

• Applied Biological Chemistry
• /
• v.39 no.4
• /
• pp.268-273
• /
• 1996

Fundamental data for new type of product development from Lycii fructus was experimentally determined. The chemical composition, and Hunter value changes, optimum extraction, volatile components of extract under different extraction conditions and heat treatment were mainly studied. Results are summarized as follows. The proximate compositions of dried Lycii fructus were water 21.8%, total sugar 27.6%, reducing sugar 15.2%, crude protein 14.29%, crude fat 5.65%, crude fiber 7.48%, and ash 7.98% in percent stale, respectively. Extracted yield on the basic of solid extract was getting increased when more solvent was used for extraction. The most recommendable extraction was 1 to 10 part of sample to solvent ratio. When water was employed as extraction solvent, the highest amount of solid extract was obtained. Extract of Lycii fructus in terms of yields and color was most acceptable when raw sample was treated 8 minute roasting at $180^{\circ}C$ and 60 minute heating at $120^{\circ}C$, respectively. Major volatile components of fresh Lycii fructus were to hexadecanoic acid, methyl linoleate, benzyl alcohol, dimetane benzene by GC/MS. By the roasting of raw sample, the compounds of 2-methyl-2buthenal, 1,4-dimethyl benzene, and benzyl alcohol were reduced. Wheras, methyl thiopropanol, benzene acetaldehyde and ethyl linoleate were slightly increased.

• Food Science and Preservation
• /
• v.15 no.4
• /
• pp.524-531
• /
• 2008

To investigate tea prepared from Ixeris dentata root, color, and levels of free sugars, organic acids, cynaroside, total polyphenolics, and free amino acids were investigated using various thermal processing methods. These included natural drying(ND), hot-air drying(HAD, $75^{\circ}C$), hot-air drying after steam(HADS, steaming at $95^{\circ}C$ for 30 min) and roasting after hot-air drying(RHAD, roasting at $140^{\circ}C$ for $2{\sim}3$ min). Total free sugars, organic acids, cynaroside, and free amino acids contents were highest after ND treatment. Total polyphenolics was highest after RHAD processing. The level of cynaroside, a principal component of Ixeris dentata root, was significantly decreased by HADS. The major free sugars were fructose, glucose and sucrose. Succinic acid was prominent among organic acids, and was present at 2.25%(v/v) after ND treatment. The lightness(L), redness(a), and yellowness(b) of all dried Ixeris dentata root powders were best after RHAD treatment, but analysis of the leaching liquids after hot water treatment yielded variable results. Lightness and redness were the highest after RHAD and yellowness was the highest after ND treatment. Overall, the RHAD drying method was found to be superior to other methods, in sensory evaluation tests.