• Title/Summary/Keyword: Freezing-melting

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Rates and Factors of Path Widening in Seongpanak Hiking Trail of Mount Halla, Jeju Island (한라산 성판악 등산로 노폭의 확대 속도와 요인)

  • Kim, Tae-Ho
    • Journal of the Korean Geographical Society
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    • v.43 no.3
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    • pp.296-311
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    • 2008
  • In order to examine the rates and factors of path widening in Mount Halla, the retreat of path sidewalls was monitored at 32 sites of Seongpanak Hiking Trail located between 875 m and 1,400 m in elevation. The mean rate of sidewall retreat for the period 2002-2008 is 50.6 mm, equivalent to 10.0 mm/yr. The retreat rate of frozen period is 19.3 mm/yr, while the rate of unfrozen period is 4.3 mm/yr. The latter is divided into the rainy and dry periods that exhibit the retreat rates of 5.9 mm/yr and 2.9 mm/yr, respectively. The retreat rate of sidewalls is also varied with seasons; winter shows the maximum rate of 42.2 mm/yr, while summer exhibits the minimum rate of 1.3 mm/yr. Spring and fall show the intermediate rates of 13.9 mm/yr and 6.4 mm/yr, respectively. Soil hardness and elevation are not closely related to the retreat rate of sidewalls, even though the retreat rate is larger at the north-faced sidewalls than the south-faced sidewalls during the frozen period. Pipkrake is likely to be the most important factor contributing to the path widening in that the retreat of winter months accounts for 76.7% of the total retreat. The hiking trail is placed under the climatic conditions which develop pipkrake in 85 days annually. In addition, it is usual to observe the path sidewall covered with pipkrake in the freezing month of December and the thawing months of March and April. On the other hand, deflation and rainsplash erosion are not important due to the weak wind speed and the forested trail. Rainwash is also insignificant in that the path has been almost paved to mitigate trampling effects. Although biological activity is not dominant, hikers cause a large retreat of sidewalls in the thawing months since they would walk on the sidewalls to avoid snow-melting pools on the path.

Effect of Feeding Mugwort (Artemisia capillaris) TMR Fodder on Physicochemical and Sensory Characteristics of Hanwoo Rump Meat (인진쑥 TMR 사료 급여가 한우 우둔 부위의 이화학적 및 관능적 특성에 미치는 영향)

  • Moon, Yoon-Hee;Yang, Jong-Beom;Jung, In-Chul
    • Journal of the East Asian Society of Dietary Life
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    • v.21 no.3
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    • pp.345-352
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    • 2011
  • TMR feed was developed by adding mugwort (Artemisia capillaris), and was fed to Hanwoo cattle to investigate the effects of feeding mugwort on the physicochemical and sensory characteristics of rump meat, and to determine the feasibility of producing Hanwoo beef with high quality and functionality. The experimental samples consisted of the Hanwoo rump from cattle fed with fattening TMR feed without mugwort (T0), and those fed with fattening cattle TMR feed supplemented with mugwort (T1). T1 was significantly higher than T0 for Hanwoo rump characteristics of Hunter's $L^*$, $a^*$, $b^*$ values (p<0.05). VBN content for T0 was significantly higher than for T1, and EDA for T1 was significantly higher than for T0 (p<0.05). There was no significant difference between T0 and T1 in terms of pH, TBARS, and total bacterial numbers. Water holding capacity for T1 was significantly higher than for T0 (p<0.05), but there was no significant difference between T0 and T1 in terms of freezing loss, thawing loss, and cooking loss. Springiness for T1 was significantly higher than for T0 (p<0.05), and there was no significant difference between T0 and T1 in terms of hardness, cohesiveness, gumminess, chewiness, and shear force. There was no significant difference between T0 and T1 in terms of acid value, peroxide value, and iodine value. However, the melting point for T1 was significantly lower than for T0 (p<0.05). Aroma of raw meat for T1 was significantly superior to aroma for T0 (p<0.05). Taste, palatability of boiled meat, and juiciness of roasted meat for T1 were significantly superior to those parameters for T0 (p<0.05). These results suggest that the feed containing mugwort can be used to improve color and sensory characteristics, inhibit VBN formation, and also to increase antioxidant ability as a functional feed.

Degree of Retrogradation of Non-Waxy and Waxy Rice Cakes during Storage determined by DSC and Enzymatic Methods (DSC와 효소법을 이용한 멥쌀 밑 찹쌀떡의 노화도에 관한 연구)

  • 김창순
    • Korean journal of food and cookery science
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    • v.12 no.2
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    • pp.186-192
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    • 1996
  • Retrogradation of non-waxy rice (NWR) and waxy rice (WR) cakes (45% moisture) stored at 5$^{\circ}C$, $25^{\circ}C$ and -2$0^{\circ}C$ was studied by differential scanning calorimetry (DSC) and enzymatic ($\beta$-amylase-puuulanase) method. With DSC, endotherms did not appear with rice cakes stored at room ($25^{\circ}C$) and deep freezing (-2$0^{\circ}C$) temperatures but did with samples stored at low temperature (5$^{\circ}C$), showing accelerated retrogradation by low temperature. Onset temperature (To) and peak temperature (Tp) did not change under 14 days at 5$^{\circ}C$ but enthalpy values ($\Delta$H) increased rapidly within one day and increased steadily until 5th day of storage, then equilibrated. Higher $\Delta$H were obtained with WR cakes than NWR cakes. It was suggested that more amylopectin recrystallization occured with WR than NWR. Degrees of gelatinization of rice cakes determined by enzymatic method increased in the following order: 5$^{\circ}C$ < $25^{\circ}C$ < -2$0^{\circ}C$. In contrast with DSC results, dogrees of gelatinization of NWR cakes, were relatively lower than that of WR cakes. However, increased retrogradation extents (melting enthalpies) caused reduced enzyme susceptibilities to $\beta$-amylase-pullulanase system, among NWR or WR cakes stored at 5$^{\circ}C$. The degrees of retrogradation of rice cakes stored at 5$^{\circ}C$ were higher than those stored at $25^{\circ}C$ and -2$0^{\circ}C$ without regard to the kind of rice. The higher sensitivity of the enzymatic method was obtained than that of DSC method when the degrees of retrogradation of rice cakes were determined during storage under this experiment conditions.

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