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第三部份:食品保存與微生物. 高溫保存 Preservation by High Temperature. 黃顯宗 東吳大學 M202. 都是高溫殺菌. 教學目標. 瞭解微生物的耐熱性 瞭解高溫保存食品考慮的因素 認識罐頭 -- 高溫加工的歷史與過程 瞭解如何確立食品的高溫加工過程?. High Temperature Treatment. Canning, sterilization 製罐 Pasteurilization 低溫殺菌 Frying 炒 Deep Frying 炸 Baking, Roasting 烘烤 …. 微生物的適溫性.

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slide3
教學目標
  • 瞭解微生物的耐熱性
  • 瞭解高溫保存食品考慮的因素
  • 認識罐頭--高溫加工的歷史與過程
  • 瞭解如何確立食品的高溫加工過程?
high temperature treatment
High Temperature Treatment
  • Canning, sterilization 製罐
  • Pasteurilization 低溫殺菌
  • Frying 炒
  • Deep Frying 炸
  • Baking, Roasting 烘烤
  • ….
slide5
微生物的適溫性
  • Psychrophiles
  • Mesophiles
  • Thermophiles
  • Durics vs philics
slide6
微生物的適溫性

Ayres et al., 1980

slide7
影響微生物耐熱性的因素
  • 孢子數目與營養細胞比
  • 微生物種類
    • 球菌較為抗熱,最適溫度高者較抗熱有capsule者較抗熱,有較多fatty acid者
  • 微生物先前的生長歷史
    • Culture medium
    • Temperature of incubation
    • Phase of growth
    • Desiccation
slide9
環境壓力的適應性
  • Environmental Stresses
    • Starvation, heat shock, salinity, acidity
  • Sublethal stress treatment
  • Adaptation
  • Cross-protection
  • Mechanisms
slide10
搶答
  • 蛤蜊濃湯和香菇雞湯相比,何者需要比較高的熱能殺菌?
slide11
熱加工考量因素
  • 孢子處理所在的基質
    • Moisture
    • pH
      • Low-acid food pH > 5.3
      • Medium-acid food pH 4.5 ~ 5.3
      • High-acid food pH < 3.7
  • Other constitutent
    • 如糖類,影響熱傳送
slide14
食品的酸鹼度

Ayres et al., 1980

slide15
高溫加工各種參數
  • TDT:殺死某菌量所須的熱能
  • D value:在某溫度下殺死1 log值菌所需要的時間 D0:250F
  • Z value:減少1 log值時間所需要增加的溫度
  • F value:加工所需要的總加熱時間 F0:250F
  • Lethality value:在某溫度 1 min 的殺菌效果相當於250F多少分鐘的殺菌力
d value
D value
  • 定義:在某溫度下殺死1 log值菌所需要的時間 D0:250℉
  • 怎樣測得D value?

Ayres et al., 1980

slide20
問答
  • 殺死1 log值的菌 等於
    • 殺死10個菌
    • 殺死100個菌
    • 殺死10%的菌
    • 殺死90%的菌
  • 殺死2 log值的菌 等於殺死多少%
d value21
D value
  • 減少一個對數值菌數所需要的劑量(dosage)
  • UV
  • 藥劑處理,如氯
value
Z value
  • Z value:減少1 log值時間所需要增加的溫度
  • 描述菌株的耐熱性,需要D value 和 Z value
f value and lethality value
F value and Lethality value
  • F value:加工所需要的總加熱時間 F0:250F
  • Lethality value:在某溫度 1 min 相當於250F多少分鐘的殺菌力

Ayres et al., 1980

12d concept
12D CONCEPT
  • Clostridium bitulinum Type A 的Do=0.21 min
  • 12D=12X0.21

=2.52 min

  • Low acid food 的最低公共安全要求便是

Fo=3 min

history of canning
History of Canning
  • 1809 Nicholas Appert發明 (玻璃罐)
  • 1819 Peter Durand 發明鐵罐
  • 1826 William Underwood 大量生產
  • 1839 鐵皮加上Tin-coat 防鏽 內有法郎質
  • 1872 A.K. Shriver 發明 closed steam-pressure retort
  • 1908 發明三片罐 Three-piece can
  • 1938 發明紙盒包裝鮮乳
  • 1960 發明鋁箔塑膠復合材料包裝 如 Pouch
steps in canning
Steps in Canning
  • Preparation
  • Blanching 殺菁
  • Filling
  • Exhausting
  • Sealing
  • Thermal Processing
  • Cooling
  • Storage
slide27
Cans
  • 3-piece and 2-piece cans
retort
Retort 鍋爐

http://www.foodscience.afisc.csiro.au/fpc/Images/Medium/Retort.jpg

heat treaments
Heat Treaments
  • Pasteurization
    • 過熱會傷害品質,如牛乳只殺部份微生物如病源菌
    • LTH, low temperature long time (holding) 62.8C 30min 牛乳
    • HTST, high temperature short time

71.7 C 15 sec 牛乳

http://blog8.fc2.com/h/hsiu/file/milk3.jpg

heat treaments31
Heat Treaments
  • Heating above 100C

UHT, ultrahigh temp.

http://cms.2456.com/mmmv207/adsale/media/20050927200815dairy1.JPG

http://www.diversifiedfoods.com/images/DFI__UHT8_Combo_8whiW300h.jpg

slide32
加工過程
  • 測罐頭內部品溫的變化
  • 用測試菌株測試效果

Ayres et al., 1980

slide34
討論
  • 甚麼食品不適合製作成罐頭?
  • 罐頭會有甚麼樣的微生物污染?