Dairy Foods.

Presentation on theme: "Dairy Foods."— Presentation transcript:

1 Dairy Foods

2 Dairy Queen, often abbreviated to DQ, is an international chain of soft serve and fast food restaurants. The name is taken from the name of their soft serve product which the company refers to as "Dairy Queen" or "DQ".

3 Species Water Fat Casein Whey Lactose Ash Energy Human 87.1 4.5 0.4 0.5 7.1 0.2 72 Rat 79.0 10.3 6.4 2.0 2.6 1.3 137 Dolphin 58.3 33.0 3.9 2.9 1.1 0.7 329 Dog 76.4 10.7 5.1 2.3 3.3 1.2 139 Horse 88.8 1.9 6.2 52 Cow 87.3 0.6 4.6 66 Deer 66.7 18.0 8.6 1.5 2.8 214 Milk is for mammals the main nutritive source for the young while they have their greatest relative growth. Therefore the amount of milk and its composition produced by the lactation animal is very well adapted to the special needs of the young. The variation in milk composition between species is various

4 Lactation curves of various species
As an example, reindeer which are living in very cold areas, need to be provided with a thick adipose tissue under the skin whereby the milk consumed by the young has a high fat content in order to quickly develop the protecting adipose tissue. The pups of the rat are born naked and therefore need milk with a composition of the protein adapted to development of the fur coat. The shape of the lactation curve differs among different species. Larger animals such as cows and goats have long lactation curves with peak production in the beginning of lactation, whereas smaller animals such as rabbits and rats have a short and conical curve, demonstrated in the picture below. In spite of the different species having different demands on composition and yield of milk, the production capacity is almost the same for all animals. Calculated from the correlation between the amount of milk produced per day and body weight it can be summarised that the milk producing capacity is around 1.7 ml milk/gram milk secreting tissue per day, demonstrated in the picture below. The modern lactating dairy cow has a much higher milk production than the calf needs. This is the result of the genetic breeding programs and the great improvements in feeding and management. Furthermore, the consumer demands on milk composition are not fully related to the biological capacity of the ruminants. Consumers and the dairy industry prefer a milk with a low fat content and high protein content. Therefore efforts are made to produce such a milk through breeding and by feeding. This alteration of milk yield and milk composition puts special demands on the modern lactating dairy cow. 1.7ml/g body

5 The modern lactating dairy cow has a much higher milk production than the calf needs. This is the result of the genetic breeding programs and the great improvements in feeding and management. Furthermore, the consumer demands on milk composition are not fully related to the biological capacity of the ruminants. Consumers and the dairy industry prefer a milk with a low fat content and high protein content. Therefore efforts are made to produce such a milk through breeding and by feeding. This alteration of milk yield and milk composition puts special demands on the modern lactating dairy cow.

6 Milk Production

7 주요유제품 1인당 소비량 (kg)

8 발효유 (kg)

9 치즈 (kg)

10 Milk Science 우유의 성분 비유기 (lactation stage), 연령, 계절, 착유간격, 사료, 환경온도, 질병이 주요한 영향을 미친다. Composition can vary according to: Species Strain or breed of animal Stage of Lactation Stage of milk removal Milk fat is the most variable component. Lactose is the least variable component. 보통 우유의 경우에도 성분조성은 비유기에 따라 변화한다. 어ayrshire 종을 사용한 경우 무지고형분과 단백질은 비유개시후 약 50일만에 최저수준에 이르고 지방함량은 약 70일 후에 최저수준에 이르고 lactose 는 약 45일째에 최고함량이었다. 젖소의 연령도 큰 영향을 미치는 데 27월령-28월로 우유를 생산하기 시작하여 10세-12세까지 8-10년을 경제년한으로 보고 있는데 2-3세경에는 농후한 편이나 생산량이 적고 연령에 따라 생산량은 증가되나 묽어지는 것으로 알려져 있다. 우유의 성분조성은 착유중에도 변하는 것으로 나타난다. 착유 맨마지막에는 지방이 높게 나타나고 있다. 계절에 따라서도 성분조성은 차이난다. 초여름에 최저치를 나타내고 무지고형함량도 7월경에 최저치를 나타낸다. 우유성분조성에 가장 현저한 영향을 미치는 요인은 질병이다. 특히 유방염은 가장걸리기 쉬운 질환으로 우유 생산량이 현저하게 감소된다. Lactose ranges from only a trace to less than 7%. Some species have very little lactose in milk, such as the bear and kangaroo. These must have some other osmole in order to maintain milk in osmotic balance with blood plasma as milk is being synthesized. These species often have another sugar (for example the kangaroo has a trisaccharide) as the major osmole. Milk fat is the most variable component of milk. It ranges from a little over 1% to greater than 50 %. Aquatic mammals typically have high milk fat percentage. Milk protein concentration varies considerably, but not as much as milk fat varies among species. Ranges from 1% to about 14%. Generally milk protein percentage is positively correlated with milk fat percentage. If one is high, the other is usually high.

11 Lactose is a disaccharide composed of D-galactose and
is the major carbohydrate in milk. is present in milk of most mammals. is a readily digestible source of glucose (energy) for the neonate. is digested by lactase enzyme in the neonate. is unique to the mammary gland. is the major osmole of milk (the primary component that draws water into the gland). Lactose is the major carbohydrate in the milk of most species. Lactose is a disaccharide composed of the monosaccharides D-glucose and D-galactose, joined in a ß-1,4-glycosidic linkage. The chemical name for lactose is 4-0-ß-D-galactopyranosyl-D-glucopyranose. It is essentially unique to milk, although it has been identified in the fruit of certain plants. Of the mammalian species where information is available, only some marsupials have an alternative sugar other than lactose, and those sugars are generally trisaccharides of glucose and galactose. Lactose plays a major role in milk synthesis. It is the major osmole in milk and the process of synthesis of lactose is responsible for drawing water into the milk as it is being formed in the mammary epithelial cells. Because of the close relationship between lactose synthesis and the amount of water drawn into milk, lactose content is the least variable component of milk. 우유속에 들어있는 탄수화물의 대부분을 차지하고 있는 것은 lactose 이다. 바다사자나 바다표범의 젖에는 전혀 lactose 가 들어있지 않으며 어떤 젖에는 lactose 외에도 다른 종류의 탄수화물의 함량이 높아 진화생화학자들에게 관심사가 되고 있기도 하다. 모유는 우유에 비하여 lactose 함량이 높으며 lactose 이외의 oligosaccharide 의 함량이 높은 것도 특징의 하나이다. Lactose 는 알파와 베타 두가지 형태로 존재하는데 보통 시판용의 lactose 는 알파를 가리킨다. 이 알파는 결정화의 조건에 따라 여러가지의 결정형을 가지고 있는 것으로 알려지고 있다. 압력이 높고 결정화속도가 빠르면 , 또 압력을 줄이면, 여러가지 결정형이 생겨난다. Lactose is a disaccharide composed of D-galactose and D-glucose.                                                         

12 Lactose Intolerance Lactase Lactose Galactose + Glucose
Lactose intolerance is the inability to metabolize lactose, because the required enzyme lactase is absent in the intestinal system or its availability is lowered. It is estimated that 75% of adults worldwide show some decrease in lactase activity during adulthood.[1] The frequency of decreased lactase activity ranges from nearly 5% in northern Europe, up to 71% for Southern Europe, to more than 90% in some African and Asian countries.[2] Lactase 는 자연에 널리 분포되어 있는 효소로 고등동식물체에는 물론 효모, 세균 등에서 생합성되고 있으며 lactose 에 작용하여 galactose 와 glucose를 생성시킨다. 이 효소는 반응생성물인 galactose 에 의하여서는 저해를 받으나 glucose 에 의하여 서는 영향을 받지 않는다. Lactose는 다른 당류와는 달리 몇가지 생리적 활성을 나타내고 있는데 이 생리활성에는 lactose 가 직접 관계하기도 하며 lactose 의 가수분해물인 galactoserk 관계되기도 한다. 소화관에서 lactose는 소장점막에서 합성된 베타 galactosidase 에 의해 가수분해되어 단당류로 되어 흡수, 이용된다. 그런데 비백인계의 많은 지역에서는 우유를 음용한뒤에 속이 거북해지거나 설사를 하는 증세를 나타내는데 이것을 lactose 불인증 (lactose intolerance) 라고 한다. 이것은 소장점막에서의 lactase 결핍에 의한 것으로 알려지고 있으며 조사에 의하며 구미백인사회에서는 2% 미국의 흑인인구의 70%, 아프라카인의 95%, 아시아인의 약 90%가 이 증상을 나타낸다 년대의 발표에 의하면 이유후에 우유를 음용하지 않는데서 오는 증세로 유전인자에 까지 영향을 미칠수 있다고 한다. Lactose 가 lactase에 의하여 가수분해되지 않고 흡수되거나 lactose를 대량섭취하거나 lactoserk 뇨중에 섞여 나오기도 하는데 이 증세를 lactouria 병이라고 한다. Lactose는 흡수속도가 늦기 때문에 장에 이르면 미생물에 의하여 발효되어 lactic acid 가 형성된다. 그 결과 장내의 pH 를 저하시키게 되며 장내에서의 칼슘이온의 흡수를 촉진시키게 된다. 많은 연구자들은 lactose 가 칼슘 뿐 아니라 알칼리 족 이온의 흡수속도를 높이며 콜레스테롤의 흡수속도와 대사속도도 촉진시킨다고 발표하고 있다.

13 Lactose is the major osmole in milk
There is no gradient of water maintained between blood and milk. Cell membranes act to restrict diffusion of water. Cell membranes are semipermeable, that is they permit water to move across, but not many solutes move freely across cell membranes. Osmosis - the spontaneous flow of water across a membrane, down a concentration gradient of water. Osmotic pressure - the pressure required to prevent osmotic flow (osmosis of water into a given solution). Isosmotic - When two solutions with the same osmotic pressure are isosmotic Synthesis of lactose in the Golgi results in an impermeant small molecule that is formed effectively at an extracytoplasmic site. Water is osmotically drawn into the Golgi/secretory vesicles to try to dilute the lactose. Lactose accounts for ~50% of the osmotic pressure of milk (the rest is citrate, ions, proteins, etc.). This flow of water probably induces an electrical potential difference across the apical membrane when the secretory vesicles fuse with the apical membrane and release their contents. The electrical potential causes Na+ and K+ to preferentially return to the intracellular (cytoplasmic) fluid, even against a concentration gradient. The apical membrane is impermeant to Ca, citrate and phosphate - these do not flow back into the cell. Ducts are impermeable to the major constituents of milk. There is no resorption of water in the ducts. Ducts act only as a conduit for moving milk from alveoli to the teat and the large ducts for passive storage of milk between milk removals. THEREFORE, the ionic composition of milk is determined in the secretory alveolar cells. The concentration of lactose in milk is inversely related to the molar sum of K+ and Na+ in milk. Lactose synthesis keeps milk K+ and Na+ low. Species differences in lactose : ion ratios may be due to differences in the rates of lactose synthesis and in water permeability across cell membranes. Blood and milk are isosmotic (6.6 atmospheres), but are not in chemical equilibrium:

14 Milk Fat Milk Fat : is primarily triglycerides fatty acids bound to 1 glycerol is initially used by neonate for deposition of body adipose is an energy source for the neonate. is secreted as a milk fat globule. - bounded by a lipid-bylayer membrane is extremely variable in concentration between species and within a species. is dispersed when milk is homogenized.

15 Milk Fat Milk fat is composed of a complex mixture of lipids. Triglycerides are the major type of lipid in milk fat. Triglycerides are composed of three fatty acids covalently bound to a glycerol molecule by ester bonds. Milk fat is the major source of lipid used by the neonate mammal for accumulating body adipose in the initial days after birth. Most mammalian neonates are born with little body adipose for insulation or as a source of stored energy. A few days after birth most neonates begin to be able to metabolize milk fat as an energy source. Adipocytes of the mammary fat pad. These fat cells are similar to the body adipose cells. Note the broad sheaths of dense connective tissue (stained red in this image) that course through the lobules of adipocytes. Neonate:신생아

16 If milk is left to stand, a layer of cream forms on the surface
If milk is left to stand, a layer of cream forms on the surface. The cream differs considerably in appearance from the lower layer of skim milk. Under the microscope cream can be seen to consist of a large number of spheres of varying sizes floating in the milk. Each sphere is surrounded by a thin skin—the fat globule membrane—which acts as the emulsifying agent for the fat suspended in milk The membrane protects the fat from enzymes and prevents the globules coalescing into butter grains. The fat is present as an oil-in-water emulsion: this emulsion can be broken by mechanical action such as shaking Fat globule

17 Milk Fat Milk fat is secreted from mammary epithelial cells as fat globules which are primarily composed of a globule of triglyceride surrounded by a lipid bilayer membrane similar to the apical membrane of the epithelial cells (discussed in more detail in the Lesson on Milk Fat Synthesis). This fat globule membrane helps to stabilize the fat globules in an emulsion within the aqueous environment of milk (remember that cow milk is about 87% water). Lipid has a lower buoyant density than water, so when raw milk is centrifuged the fat rises to the top resulting in the cream layer (see image at right). Milk fat is the primary component of cream. Below milk was centrifuged to separate the cream and the skim milk (also called the plasma phase of milk). There are so many fat globules that they also carry some of the milk protein to the top, so cream also contains a small amount of protein in addition to the milk fat component; this protein component contributes to the whipping characteristics of cream. The stability of the fat emulsion in milk can be overcome by allowing raw milk to stand for a period of time, which results in the cream rising to the top. This is especially true for high fat milks such as those from the Jersey and Guernsey breeds.

18 Milk Proteins There are several types of proteins in milk. The major milk proteins are unique to milk. - not found in any other tissue Milk proteins, particularly caseins, have an appropriate amino acid composition for growth and development of the young. Other proteins in milk include an array of enzymes, proteins involved in transporting nutrients, proteins involved in disease resistance (antibodies and others), growth factors, etc. 우유의 단백질 함량은 3% 내외를 나타내는데 우유속에 많은 종류의 단백질 들어있음을 물리적으로 밝힌것은 1936년경이다. 다음과 같이 다섯구분의 질소태 즉, 카제인 태 질소, 비 카제인 비단백질태 질소, proteose-peptone 태 질소 및 lactalbuminxo 질소를 분획하였다. 우유 단백질은 카제인이 78.3%, albumin이 9.1%, globulin이 3.5%, proteose-peptone 이 4.1 % 그리고 비단백질태질소가 5.0% Casein 78.3%, albumin 9.1%, globulin 3.5%, proteose-peptone 4.1, non-protein nitrogen compounds 5.0%

19 Proteins (30-35g/l) Minor protein Enzymes Caseins (76-86%) Α-casein (60%) β-caseins (25-35%) γ-caseins (3-7%) Whey protein (14-24%) Lactoglobulin (7-12%) Lactalbumin (2-5%) Immunoglobulins ( %) Blood serum albumin ( %) Proteose-peptones (2-6%)

20 Casein Caseins is composed of several similar proteins which form a multi-molecular, granular structure called a casein micelle. the casein micelle contains water and salts (mainly calcium and phosphorous). Some enzymes are associated with casein micelles. The micellar structure of casein in milk is an important -the mode of digestion of milk in the stomach and intestine the basis for many of the milk products industries (such as the cheese industry) the basis for our ability to easily separate some proteins and other components from cow milk. Casein is one of the most abundant organic components of milk, in addition to the lactose and milk fat. Individual molecules of casein alone are not very soluble in the aqueous environment of milk. However, the casein micelle granules are maintained as a colloidal suspension in milk. If the micellar structure is disturbed, the micelles may come apart and the casein may come out of solution, forming the gelatinous material of the curd. This is part of the basis for formation of all non-fluid milk products like cheese Casein consists of a fairly high number of glycine peptides, which do not interact. There are also no disulfide bridges. As a result, it has relatively little tertiary structure. Because of this, it cannot denature. It is relatively hydrophobic, making it poorly soluble in water. It is found in milk as a suspension of particles called casein micelles which show some resemblance with surfactant-type micellae in a sense that the hydrophilic parts reside at the surface. The caseins in the micelles are held together by calcium ions and hydrophobic interactions

21 Acid, proteolytic enzyme (rennin) Centrifugation
Milk Milk Acid, proteolytic enzyme (rennin) Centrifugation Curd Whey Casein Whey Water non-casein protein lactose Casein Water non-casein protein lactose A classic precipitation method for casein in cow milk which is done in the laboratory is to slowly add HCl (0.1 N) to lower the milk pH to 4.6. The casein will gradually form a precipitate while relatively little of the other milk proteins will precipitate. Different combinations of controlled acid precipitation and enzymatic hydrolysis of casein are the foundation of the cheese industries. Often specific bacterial cultures are used to establish the conditions for lowered pH and secretion of proteolytic enzymes which form the different types of cheese.

22 Foods from Milk… based on its scientific facts
Supernatant Whole milk solids Protein Casein Whey protein Whey Hard cheese Cottage cheese Lactose Lactic acid acetic acid propionic acid aldehydes bacterial fermentation Separate milk Cream 35% fat Churn cream Butter 82% fat Remove moisture Butter or oil 99% fat Precipitate pH 4.6 Fat

23 유제품들의 제조공정

24 시유 (market milk) Clarification Standardiza-tion Measurement Inspection
Storage (Aging) Homogeni- zation 표준화 Distribution Inspection Packaging Pasteurization

25 Clarification Separation and clarification can be done at the same time in one centrifuge. Particles, which are more dense than the continuous milk phase, are thrown back to the perimeter. The solids that collect in the centrifuge consist of dirt, epithelial cells, leucocytes, corpuscles, bacteria sediment and sludge. The amount of solids that collect will vary, however, it must be removed from the centrifuge. More modern centrifuges are self-cleaning allowing a continuous separation/clarification process. This type of centrifuge consists of a specially constructed bowl with peripheral discharge slots. These slots are kept closed under pressure. With a momentary release of pressure, for about 0.15 s, the contents of sediment space are evacuated. This can mean anywhere from 8 to 25 L are ejected at intervals of 60 min. For one dairy, self-cleaning translated to a loss of 50 L/hr of milk. The following image is a schematic of both a clarifier and a separator.

26 시유-표준화(standardization)
생산하려는 제품의 종류와 규격에 따라 원유의 지방, 무지고형분(solids-not-fat),강화성분등을 조성하고, 기타 첨가되는 원료의 적당량을 결정하여 완제품의 조성분 규격에 맞도록 하는 작업 Pearson 의 square method 를 이용하여 혼합량을 정한다. 예를 들면 지방률이 4.0 인 우유와 2.0%의 우유를 혼합하여 지방률 3.0%의 우유로 조정하려면 다음과 같이 계산하여 각각 50% 씩 혼합시키게된다. The streams of skim and cream after separation must be recombined to a specified fat content. This can be done by adjusting the throttling valve of the cream outlet; if the valve is completely closed, all milk will be discharged through the skim milk outlet. As the valve is progressively opened, larger amounts of cream with diminishing fat contents are discharged from the cream outlet. With direct standardization the cream and skim are automatically remixed at the separator to provide the desired fat content (see diagram to explain this automatic standardization process) . Some basic standardization problems including mass balance and Pearson square approach can be viewed here. 1.0 4.0 1.0 X 100 = 50% 2.0 3.0 1.0 2.0 1.0 X 100 = 50% 2.0 2.0

27 보충-Pearson 의 square method
대두분에 45%의 crude protein 이 있다. 그리고 옥수수에 10%가 존재한다. 이 대두분과 옥수수를 각각 얼마만큼 섞어야 14%의 대두와 옥수수 혼합물을 만들 수 있는가?

28 Standardization

29 Quiz What is differences between MA and CA storage
Explain the minimally process with examples. Available day and time ?

30 Homogenization Milk is an oil-in-water emulsion, with the fat globules dispersed in a continuous skimmilk phase. If raw milk were left to stand, however, the fat would rise and form a cream layer. Homogenization is a mechanical treatment of the fat globules in milk brought about by passing milk under high pressure through a tiny orifice, which results in a decrease in the average diameter and an increase in number and surface area, of the fat globules. a decrease in the mean diameter of the fat globules (a factor in Stokes Law), a decrease in the size distribution of the fat globules (causing the speed of rise to be similar for the majority of globules such that they don't tend to cluster during creaming), and an increase in density of the globules (bringing them closer to the continuous phase) oweing to the adsorption of a protein membrane. In addition, heat pasteurization breaks down the cryo-globulin complex, which tends to cluster fat globules causing them to rise

31 시유-균질화(homogenization)
원료유를 정치하면 탈지유와 지방구의 비중차에 의하여 creaming 현상이 일어나므로 이를 방지하기 위한 공정이다. 우유 중의 지방구에 물리적 충격을 가해 지방의 크기를 ㎛ 정도의 크기로 작게 분쇄하는 작업을 균질이라한다. 균질에 의한 효과는 조직을 균일하게 하고 점도를 증가시키며, 또 curd장력을 줄여 부드러운curd를 만들기 때문에 소화율을 높이는 효과가 있다 Milk is an oil-in-water emulsion, with the fat globules dispersed in a continuous skimmilk phase. If raw milk were left to stand, however, the fat would rise and form a cream layer. Homogenization is a mechanical treatment of the fat globules in milk brought about by passing milk under high pressure through a tiny orifice, which results in a decrease in the average diameter and an increase in number and surface area, of the fat globules. The net result, from a practical view, is a much reduced tendency for creaming of fat globules. Three factors contribute to this enhanced stability of homogenized milk: a decrease in the mean diameter of the fat globules (a factor in Stokes Law), a decrease in the size distribution of the fat globules (causing the speed of rise to be similar for the majority of globules such that they don't tend to cluster during creaming), and an increase in density of the globules (bringing them closer to the continuous phase) oweing to the adsorption of a protein membrane. In addition, heat pasteurization breaks down the cryo-globulin complex, which tends to cluster fat globules causing them to rise.

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33 시유-살균 살균방법에는 저온장시간살균법,고온단시간살균법,초고온살균법으로 나눈다. ▶ 저온장시간살균법 (LTLT:low temperature long time pasteurization method) -원유를 63-65℃에서 30분간 가열하는 방법 ▶ 고온단시간살균법 (HTST:high temperature short time pasteurization method) -원유를 72-75℃에서 15-20초간 가열하는 방법 ▶ 초고온살균법 (UHT:ultra high temperature pasteurization method) -원유를 ℃에서 0.5-5초간 가열하는 방법

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35 시유-검사법 일반검사: 비중, 산도, 지방함량, pH, 항생물질의 유무 관능검사: 색깔, 냄새
의심스러운 것은 alcohol test 와 세균수측정을 행한다. 비중: 우유비중계를 사용한다. 300ml mass cylinder에 200ml 우유를 붓고 비중계를 꽂고 눈금을 읽는다. 산도: titration method 를 사용한다. Lactic acid 의 양으로 환산한다. 정확한 양의 우유를 삼각 flask에 넣고 지시약으로 phenolphthalein 용액을 3-5 방울 적하하여 혼합시킨다음, 0.1N NaOH용액으로 적정한다. 미홍색이 30초동안 없어지지 않고 남아있는 점을 종말점으로 하여 다음을 이용하여 산도를 계산한다. 산도 (%) = ((0.1 N NaOH 적정 ml 수 x 0.009) / 우유의 g수) x 100

36 시유-검사법 지방함량 측정 : babcock milk test 우유의 열안정성과 신선도 판단: alcohol test
Measure milk into graduated test tube. You usually take 18 grams of milk or 17.6 milliliters. Add 17.6 milliliters of 90-92% sulfuric acid. Centrifuge at 50ºC. Measure fat which will be floating on top of liquid in the test tube 우유의 열안정성과 신선도 판단: alcohol test 5ml milk into testtube 5ml of ethyl alcohol (68%) and mix Coagulation means acidity is over 0.21% Test should be carried out below than 15C

37 발효유-액상요구르트 원료의 살균: 탈지유를 원료로 10-12% 고형분
UHT, 90C, 15-60min. 115C, 1min.  cooling 접종, 배양: 별도로 배양된 starter 를 원료액에 대해 2-2.5% 첨가후 교반 Starter: Str. Lactis, Str. Cremoris, Str. Thermonphilus Lactobacillus bulgaricus, L. acidophilus, L. casei 균질화, 조합: curd 를 homogenizer 로 균질화한후 당, 향기첨가 충진, 냉각:

38 발효유-고형요구르트 원료의 처리: 탈지유를 원료로 12-15% 고형분
gelatin, agar (thickening agent) % Vitamin, sugar, syrup 90C, 20-30min. 94C, 15min. 115C, 1min.  cooling 접종, 배양: 별도로 배양된 starter 를 원료액에 대해 2-3% 첨가후 교반 Starter: Str. Lactis, Str. Cremoris Lactobacillus bulgaricus, L. acidophilus Curd 형성 (pH ) 형성 (*활성균주는 더 빠름) 충진, 냉각:

39 우유관련 식품: ice cream 원료의 혼합 및 용해: 40-50C 온도에서 행한다. 산도 0.25% 유지
원료별 녹는 점이 다르므로 별도로 가열 처리 Mix 의 살균: 살균조건은 고온에서 행한다. 고형분함량이 높고 점도가 크기 때 문에 보호효과가 나타나므로. UHT, HTST Mix 의 균질화: 동결시에 mix의 응고를 방지하고 숙성시간을 단축하며 점도를 증가시켜 ice cream 의 body와 texture 를 개선하기 위해 Mix 의 숙성: aging tank 에서 4-24시간 보존 mix 의 점성이 증가되며 지방구의 분산이 정비. 유지방율이 15% 이상인경우 꼭 필요함. 최근에는 안정제, 유화제가 많이 첨가되어 생략할수도 있음 Mix 의 동결: ice cream mix를 부분적으로 동결시켜 반동결상태로 만듬, mix 속으로 공기를 혼입, 분산시킴

40 우유관련 식품: ice cream Mix 의 동결: 반고체상  soft icecream, ice cream mix 의 용적보다 % 증가 동결공정중에 mix 속으로 공기가 혼입, 분산되어 용적이 증가하는 현상  OVER RUN (증용량) Over run % = ((volume of ice cream-volume of mix)/volume of mix) x 100 = ((weight of mix-weight of ice cream)/weight of ice cream) x 100 경화: 적당한 용기에 soft ice cream 을 충진기에 담아 포장후 경화실에서 경화된다. -18C 이하의 온도에서 수분의 85% 이상을 동결시킨다.  hard ice cream

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44 우유관련 식품: Butter

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46 우유관련제품: Cheese

47 동영상: Cheese

48 동영상: Butter

49 보충: 소화흡수 As food passes from the stomach to the small intestine, a series of endocrine and paracrine agents prepare the small intestine, stimulate the pancreas, stimulate the release of bile and inhibit contractions of the stomach. 1. The gastrin familby includes: gastrin == secreted by the stomach which intern stimulates the release of HCl CCK = cholycystokinin, released by the presence of fats in the SI, inhibits stomach contraction, stimulates release of pancreatic enzymes  and release of bile 2. Secretin family: secretin = released by the small intestine, promotes the release if bicarbonate by the pancreas vasoactive intestinal peptide, GIP = stimulates insulin release GLP == inhibits glucagon release and ?? 3. Motilin -- promotes peristalsis

50 보충: 소화흡수 Enzymes for all three classes of foods are secreted by the pancreas in an inactive form.

51 보충: 소화흡수 Enzymes for all three classes of foods are secreted by the pancreas in an inactive form. Glucose and galactose are absorbed in a process that requires Na, fructose is absorbed through its own channel by facilitated diffusion. Since these cells are transporting glucose, they seem to use a different substrate for their own metablism -- the amino acid glutamine.  Lactose, milk sugar, is composed of glucose and galactose. The enzyme that digests lactose is lactase, it is secreted in juvenile mammals, but levels usually decline in adults leading to lactose intolerance.

52 보충: 소화흡수 Proteins are absorbed as amino acids in a process that also requires sodium, 2 and 3 AA units, and small peptides by endocytosis.  In babies, more, larger peptide units are absorbed whole, the infant can absorb the large immune globulins found in mother's milk.   Both sugars and amino acids are absorbed by the capillary circulation of the villi and carried via the hepatic portal system for processing

53 보충: 소화흡수 Fats are digested in the small intestine, with the help of the bile salts. Micelles of triglycerides are still hydrophobic enough to cross the lipid bilayer of the absorptive cells. In the cells they are processed and repackaged by the smooth endoplasmic reticulum and the golgi and are released as chylomicrons.  These packages are not able to enter capillary circulation, but are absorbed by the lymph vessels of the villus -- the lacteals.