5. Existen hasta 150 distintos. Los mas abundantes son: palmítico, esteárico, oleico, vacénico. (puede emplearse para diferenciar diversos tipos de leche)
14. While the “cis”form of geometric isomer is the most common found in nature, approximately 5% of all unsaturated bonds are in the “trans”position as a result of rumen hydrogenation.Fattyacid “cis” “trans” 7
38. Vitamin content of fresh milk VitaminContents /litre A (ug RE) 400 D (IU) 40 E (ug) 1.000 K (ug) 50 B1 (ug) 450 B2 (ug) 1750 Niacin (ug) 900 B6 (ug) 500 Pantothenicacid (ug) 3.500 Biotin (ug) 35 Folicacid (ug) 55 B12 (ug) 4.5 C (mg) 20 13
39. LECHE (Contaminantes de la leche) Químicos Provienen de contaminaciones accidentales desde el ordeño hasta el fin del proceso industrial. Los principales son: insecticidas, herbicidas, fungicidas, higienizantesy antibióticos. Algunos clientes piden análisis periódicos de estos parámetros. Biológicos Deficiencias en la higiene durante el proceso ordeño, transporte, industrialización y venta. Las bacterias y hongos trabajan conjuntamente con los enzimas. Él número total de microorganismo presentes es indicativo de las condiciones sanitarias de producción y conservación, así como de la vida comercial del producto. Bacterias Por morfología son: cocos (estreptococos y estafilococos), bacilos y espirilos. Hongos Aspecto filamentoso o algodonoso. Se nutren mayoritariamente de los azucares. 14
40. PASTEURIZACIÓN (tratamiento térmico) Higienización : Filtrado o clarificado por centrifugado. Se eliminan partículas, impurezas y esporulados. Homogenización: Reduce el tamaño de los glóbulos de grasa por choque violento de la leche a alta presión. Se trabaja a 65 – 70ºC Pasteurización Debe realizarse siempre. Es un tratamiento térmico se pretende eliminar todos los organismos patógenos y disminuir la cantidad de microorganismos. Objetivo: la menor temperatura y el menor tiempo posible. Factores son contradictorios 15
41. PASTEURIZACIÓN (tratamiento térmico) Procesos de pasteurización Lenta 30 minutos a Temperatura de 62 – 64ºC Se emplea para pequeños volúmenes de leche. Se realiza en tanques Rápida 15 a 20 segundos a temperatura 72 – 73ºC También ser llama continua y puede procesar grandes volúmenes. Se realiza en intercambiadores de placa. Para queso temperatura hasta 70ºC para evitar precipitaciones de fosfato cálcico que inducen a coagulaciones defectuosas. Para leche en polvo Descremada 3 minutos a 88ºC Entera 3 minutos a 90ºC Destrucción de las lipasas (responsables del enrranciamiento) y una reducción considerable de la flora bacteriana. 16
42. PASTEURIZACIÓN (tratamiento térmico) Influencia sobre componentes Grasa: Modifica la aglomeración de los glóbulos de grasa. Lactosa: No le afecta hasta los 100ºC Proteínas: Por encima de 80º desnaturalización de WP. Puede alterar la acción del cuajo sobre la caseína provocando inconvenientes en la elaboración de queso. Enzimas: La mas sensible es la lipasa. Vitaminas: Afecta B1, B12 y C 17
43. PASTEURIZACIÓN (tratamiento térmico) Influencia sobre microorganismos A temperaturas de 35 a 40ºC tenemos crecimiento máximo. A temperaturas superiores el crecimiento disminuye. Leches tratadas a diferentes temperaturas no se encuentran las mismas especies 18
44.
45. un SOPLADOR y que pasa por un calentador hasta alcanzar la temperatura de 150-250º C.
46. BOQUILLAS generan pequeñísimas gotas de leche , que se encuentran en la corriente de aire caliente dentro de la cámara de secado. El agua libre se evapora instantáneamente.
47. El agua contenida en el interior pasa por difusión hacia la superficie de la gotita, desde donde es evaporada por el aire caliente. Las partículas de leche nunca se llegan calentar excesivamente, ya que el calor del aire es consumido en la evaporación del agua y no en el calentamiento de dichas partículas.
48. La leche en polvo descarga por (6) pasa a la sección de envasado. El aire pasa por un CICLÓN, que recupera las partículas de polvo que contenga.19
50. Instantinización Para obtener un producto en polvo que se disuelva en agua de forma instantánea se deben obtener aglomerados porosos, para lo que se recurre a un sistema de atomización al que se conecta otro de fluidización. 21
51. DEHIDRATACION– roller SINGLE 'FINE FILM' DRUM DRYER A system developed for drying of heat sensitive materials. The tray containing the feed to the dryer drum and product film is applied by an intermediate applicator roll which may also becooled. Typical applications are: Milk products, Fine Chemicals e.g. Sodium Benzoate, Plant Extracts. 22
52. DEHIDRATACION– roller TWIN CYLINDER DRYER WITH NIP FEED The material to be dried is pumped, either directly or through spray nozzles, into the nip formed between two drying drums. This is the oldest and simplest form of drum dryer. The thickness of the product film may be varied by adjustment of the gap between the drying drumsorcylinders. Typical applications are: Drying of Yeast, Milk products, Detergents, Dyestuff manufacture. 23
53. Solubilidad de la LECHE La leche constituye un sistema complejo en el cual los glóbulos grasos se encuentran emulsionados, la caseína se presentan en suspensión coloidal y la lactosa, sales minerales y algunas vitaminas se mantienen en solución. Por lo tanto, cuando se habla de la solubilidad de la leche en polvo, realmente se trata de indicar su capacidad para regenerarse cuando se mezclan con agua, formando un producto similar a la leche natural. La solubilidad de los productos lácteos desecados tiene gran importancia comercial. Esta propiedad depende, entre otros factores, del método de elaboración, la temperatura de secado y la acidez. La leche obtenida por atomización presenta una solubilidad de casi 100%, la obtenida por el método roller es menor, de aproximadamente 80-95%. La determinación de la solubilidad de la leche en polvo se hace por método empíricos. Se mezcla una determinada cantidad de muestra con un volumen estipulado de agua, bajo condiciones especiales, determinando el residuo insoluble por medición volumétrica, por pesada, o bien determinando los sólidos totales disueltos. 24
54. Whey Protein Nitrogen Index WPNI mg/g powder Low heat powder: not less than 6 Medium heat powder: above 1.5, but below 6 High heat powder: not more than 1.5 Expresses the amount of undenatured whey proteins in the powder and is a measure for the heat treatment to which the milk has been exposed during the production. Standardization of NFDMwithlactose can changeitscomposition, WPNIvalue and effectitsheatclassification. The amount of heat used to produce NFDMaffects solubility of the protein with high heat powder slightly less soluble than low heat powder. 25
55. ScorchedParticleStandards Results Compare the results with the original ADMI standard chart. The comparison is visual. The standard chart is divided into a scale from A-D, where: A = 7.5 mg B = 15.0 mg C = 22.5 mg D = 32.5 mg If a sample is classified as being between two standards it is always set at the highest value. A sketch of the ADMI chart is shown on Fig. 1. 26
56. Acidez Titratable acidity The titrable acidity of milk is the amount of a hydroxyl ion (OH-) solution of a given strength needed to increase the pH of a given amount of milk to a pH of about 8.4, the pH at which the normally used indicator, phenolphtalein, changes colour from colourless to pink. If milk sours on account of bacterial activity, an increased quantity of alkali is required and so the acidity or titration value of the milk increases. The titratable acidity can be expressed in various values: °SH = Soxhlet Henkel degrees, obtained by titrating 100 ml of milk with N/4 NaOH , using phenolphtalein as the indicator. Normal milks give values about 7. This method is mostly used in Central Europe. °Th = Therner degrees, obtained by titrating 100 ml of milk, thinned with 2 parks of distilled water, with N/l0 NaOH, using phenolphtalein as the indicator. Normal milks give values about 17. Mostly used in Sweden and the CIS, °D = Dornic degrees, obtained by titrating 100 ml of milk with N/9 NaOH, using phenolphtalein as the indicator. Normal milks give values about 15. Mostly used in the Netherlands and France. % lactic acid = per cent lactic acid, obtained as °D with the result divided by 100. Frequently used in the UK, USA, Canada, Australia and New Zealand. Example: 1.7 ml of N/10 NaOH are required for titration of a 10ml sample of milk 10 × 1.7 = 17ml would therefore be needed for 100ml and the acidity of the milk is consequently 17°Th. 27
58. DryWholeMilk (DWM) ProductDefinition: Dry Whole Milk usually is obtained by the removal of water from pasteurized milk, which also may have been homogenized. Alternatively, DWM may be obtained by blending fluid, condensed or nonfat dry milk with liquid or dry cream or with fluid, condensed or dry milk, provided the resulting DWM is equivalent in composition. It contains not less than 26% but less than 40% milkfat (by weight) on an “as is” basis and not more than 5% moisture (by weight) on a milk solids-not-fat basis. Optionally, it may be fortified with either Vitamins A or D, or both. The primary DWM products are those having 26.0% and 28.5% milkfat. DWM for human consumption complies with all provisions of the U.S. Federal Food, Drug, and Cosmetic Act. MicrobiologicalAnalysis Standard PlateCount ...........................< 10,000/g Coliform .......................................................< 10/g Salmonella ............................................... negative Listeria ..................................................... negative Coagulase-positive Saphylococci............. negative TypicalCompositionalRange Percentage Protein..................................24.5 – 27.0 Lactose .................................36.0 – 38.5 Fat.........................................26.0 – 28.5 Ash .........................................5.5 – 6.5 Moisture........................ ........2.0 – 4.5 29
59. DryWholeMilk (DWM) Other Characteristics Scorched Particle Content.......... 7.5 – 15.0 mg Solubility Index…………...….................... <1.2 ml (high-heat)< 2.0 ml Titratable Acidity ................................ < 0.15% Color........................……….white to light cream Flavor.................................. clean and pleasing Production Applications and Functionality Confectionery, bakery products, packaged dry mixes, dairy products, soups, sauces, frozen foods, beverage use. Storage & Shipping Product should be stored and shipped in a cool, dry environment with temperatures below 80°F and relative humidities below 65%. Stocks should be rotated and utilized within 6 to 9 months. Packaging Multiwall kraft bags with polyethylene inner liner or other approved closed container. ( i.e. “tote bins”, etc.) Product also packaged in smaller sizes for retail sale. 30
61. Skimmilk powder Or NFDM both casein and whey proteins are present. The amount of heat used to produce NFDM affects solubility of the protein with high heat powder slightly less soluble than low heat powder. Whey protein concentrate Whey is a byproduct of cheese manufacture. Rennet, an enzyme that clots milk, or acid is added to milk thereby causing casein to join together. The milk then separates into curds and whey. The whey is drained from the curds (casein) and becomes the starting material for WPCs. The production of (WPC) is very similar to the methods used to make MPC. Ultrafiltration, evaporation and. WPCs are soluble in water because of the processes used in their manufacture. 32
62. Milk Protein Concentrate Is produced from skim milk by a series of processes that include Ultrafiltration (UF), evaporation and drying. Ultrafiltration determines the composition of the MPC. Minerals and lactose are smaller in size while proteins, including casein and whey proteins, are much larger. It is this large difference between the size of the two groups of components that allows milk to be separated efficiently by UF. MPCs can be produced with protein contents ranging from 42 to greater than 80%. Because some of the calcium is bound to casein, the concentration of calcium remains fairly constant in MPCs. Both casein and whey proteins are present. therefore, the biological protein value does not change for MPCsversus skimmilk. Because MPCproduction processes do not alter the proteins this product has good solubility. 33
63. Acid/Rennetcasein: Commercial casein is made from skim milk by one of two methods – precipitation by acid or coagulation by rennet. Fat, whey proteins, lactose and minerals must be removed from the casein through washing with water to improve the quality of the final casein product. The product is dried to improve keeping quality. Commercial casein products: 1. Precipitation by acid – Acid casein 2. Coagulation by rennet – Rennet casein There are also two other types of commercially available casein products of note: 1. Co-precipitates 2. Caseinates It is approximately 90 to 95% protein which is all in the form of casein (whey proteins are not present).The processes used to make acid and rennet casein make the products insoluble in water. Acid/rennet casein in general does not react with other components and therefore acid/rennet casein does not have a lot of functional properties. 34
64. Caseinate Have 91% protein (all in the form of casein). These products are usually salts of sodium or calcium. The neutralization process makes caseinates soluble; however, the protein will not react further with acid or rennet. Co-precipitates Calcium chloride or dilute acid is added to skim milk and the mixture then is heated to precipitate both casein and whey proteins. The precipitated proteins then are washed and dried to produce an insoluble protein mixture. The proteins can be treated with neutralizers to make a co-precipitate that is more soluble in water. Unlike acid and rennet casein, co-precipitates contain whey proteins. Calcium may be present in greater amounts because of the use of calcium chloride in the production process.Co-precipitates have 89 to 94% protein. 35
65. LECHEENTERA - en chocolate Frecuentemente la industria del CHOCOLATE prefiere la leche en polvo secada en tambores (roller-dried) frente a la secada por pulverización (spray-dried) debido a su alto contenido en grasa libre (definida como grasa extraíble por solvente), grandes partículas lamelares y ausencia de vacuolas. Sin embargo, el método de secado por spray-dried se ha convertido en el proceso estándar para la industria lechera, por ser un proceso más económico. 36