FERMENTED MILK PRODUCTS AND CHEESsE.pptx

fermented foods

1. FERMENTED MILK PRODUCTS AND CHEESE

2. Cheese Product made from the curd obtained from milk by coagulating the casein with the help of rennet or similar enzymes in the presence of lactic acid produced by added or adventitious microorganisms, from which part of the moisture has been removed by cutting, cooking and /or pressing, which has been shaped in a mould , and then ripened by holding it for some time at suitable temperature and humidity

3. Receiving Skim milk Addition of cacl 2 Addition of starter Addition of rennet Setting Cutting Cooking Drainage of whey Washing and draining the curd Salting Creaming Packaging and storage

4. Pretreatment of Milk for Cheese: Fat standardization; make adjustments to specified fat/casein ratio (approximately the ratio which defines FDM% in the classification under 20.4.4 with allowance for salt). Pasteurization is not always employed for hard cheeses; if not, the cheese must be kept for at least 60 days before consumption to ensure freedom from pathogenic bacteria. Cooling to renneting temperature, usually 30°. Transfer to cheese vat. Optional Additives Calcium chloride (5-20 grams per 100 liters) to achieve constant coagulation time. Sodium or potassium nitrate (NaNO 3 or KNO 3 ) up to 0-30 grams per 100 liters of milk to prevent gas blowing of the cheese during fermentation. Colouring agents (carotene or anatto ) to eliminate seasonal variation in carotene content; or decolouring agents (green chlorophyll, a contrast dye) to obtain a pale colour in the finished cheese (e.g. blue-veined, mould ripened cheese).

5. Necessary Additives Starter. Mesophilic cultures - 20-35°C for cheese milk conditioned at moderate temperature (Cheddar, Gouda and Cottage cheeses) and thermophilic cultures for cheese milk conditioned at relatively high temperature (Emmenthal, Gruyere and Feta varieties). Mixed cultures are often used to achieve maximum aroma and flavour development. The criteria for the starter are: (a) ability to form lactic acid in a short time; (b) ability to cause proteolysis during ripening of the cheese; and ability to produce carbon dioxide for some cheese varieties. Rennet. Except for types of fresh cheese, such as cottage cheese and quarg , in which the milk is coagulated mainly by acid, all cheese manufacture depends upon formation of curd by the action of rennet or similar enzymes.

6. General Principles Ripening varies from nil for fresh cheese to 5 years for some hard ripened cheese. Like a good wine, a good aged cheese should get better and better with age. Ripening processes classified as interior and surface ripened. Interior ripening (most hard ripened cheese such as Cheddar and Italian types) - ripened with rind formation or may be film wrapped before curing. Cheese which depend mainly on surface ripening include smear ripened and mould ripened Cheese Composition for Optimal Curing Cheese composition is critical to yield optimization, and both flavour and texture development. Moisture: higher moisture means faster ripening which means more potential for off flavours and over ripening. water activity (a w ) decreases with age because ripening results in many soluble breakdown products of acids, sugars, proteins and lipids

7. fresh Cheddar a w = 0.98 which is conducive to most bacteria aged Cheddar a w as low as 0.88 which is too low for most bacteria Higher fat restricts syneresis Fat shortens and softens cheese texture because the fat globules physically disrupt the protein matrix. In the broadest terms there are three sources of cheese flavour : Flavours present in the original cheese milk due to butter fat Breakdown products of milk proteins, fats and sugars by microbial enzymes, enzymes endogenous to milk, and enzyme additives. Metabolites of starter bacteria and other microorganisms.

8. pH Factors determining the pH at one day are amount of culture, draining pH, washing, curd treatment such as cheddaring and salting. Draining pH is most important to cheese texture and also determines residual amounts of chymosin and plasmin in the cheese. pH increases with age due to release of alkaline protein fragments. Increasing pH during curing encourages activity of both proteases and lipases Temperature of Curing Cheddar types: 4 - 10˚C, 8-10˚C is the recommended range. Low temperature initially, minimizes early growth of starter and non-starter bacteria and reduces the risk of too rapid ripening and off flavour development. It also minimizes the risk of the minimum pH reaching levels below 5.0. Surface ripened varieties are ripened at 11 - 15˚C.

9. Humidity of Curing Surface ripened cheese also require adequate air circulation to provide sufficient oxygen for moulds and yeasts. Humidity requirements in general are: Washed bacterial surface ripened: 90-95% Fungal flora: 85-90% Dry rinds: 80-85 % Packaging of cheese Vacuum and/or gas flush (N 2 and CO 2 ) in gas and moisture proof film are common. Vacuum alone is not recommended because complete evacuation of oxygen is difficult and small unsightly mould spots often appear. Gas flush with CO 2 or blends of CO 2 and N 2 effectively prevent mould growth. High density plastic (rigid containers) are used for fresh cheese such as cottage. Oxygen permeable wrap such as grease proof paper and foil-laminated but unsealed wraps, are preferred for surface ripened soft cheese

10. Paneer I s a South Asian variety of soft cheese obtained by acid and heat coagulation of milk. It is a non-fermentative, non- renneted , non-melting and unripened type of cheese. Paneer is popular throughout South Asia, used in raw form or in preparation of several varieties of culinary dishes and snacks. The production of paneer is now spreading throughout the world. The ability of paneer to be deep fried is one feature that has led to its wider acceptance and a favourite for making snacks,  pakoras  or fried paneer chunks. Paneer is a rich source of animal protein available at a comparatively lower cost and forms an important source of animal protein for vegetarians. Over and above its high protein content and digestibility, the biological value of protein in paneer is in the range of 80 to 86. Good quality paneer is characterized by a marble white colour , sweetish, mildly acidic taste, nutty flavour , spongy body and closely knit, smooth texture.

11. Manufacture process of Panner Buffalo milk having 6% fat content was heated at 82 °C in a cheese vat for 5 min and cooled to 70 °C, and was coagulated with citric acid (1% solution), which was added slowly to the milk with continuous stirring until a curd and clear whey separated out. The mixture was allowed to settle down for 10 min and the whey was drained out through a muslin cloth. During this time, the temperature of whey was maintained above 63 °C. The curd was then collected and filled in a hoop (35 × 28 × 10 cm) lined with a clean and strong muslin cloth. The hoop had a rectangular frame with the top as well as bottom open. The frame was then rested on a wooden plank and filled with the curd before covering with another plank on the top of the hoop by placing a weight of 45 kg for about 15–20 min. The pressed block of curd is removed from the hoop and cut into 6–8” pieces and immersed in pasteurized chilled water (4–6 °C) for 2–3 h. The chilled pieces of  paneer  are then removed and placed on a wooden plank for 10–15 min to drain occluded water. Afterwards, these pieces were wrapped in parchment paper, and stored at refrigeration temperature (4 ± 1 °C).

12. An industrial scale  paneer  manufacturing facility based on the above methodology was developed by the National Dairy Development Board which is commercially used ( Aneja   1997 ). In this process, the milk was heated to 85 °C and cooled to 75 °C in a plate heat exchanger and pumped to a cheese vat for coagulation and preparation as described previously. A continuous  paneer  making process was developed at National Dairy Research Institute, Karnal by Agrawala et al. ( 2001 ). In this system, the unit operations involved in  paneer  making have been mechanized. The continuous  paneer  making machine was designed to manufacture 80 kg  paneer  per hour by employing twin-flanged apron conveyor cum filtering system for obtaining the desired moisture content and texture attributes (Pal and Raju  2007 ).

13. Sensory quality of  paneer The flavor score of  paneer  decreased with decrease in the fat content of original milk utilized for the same. The panelists could not differentiate flavor profile of  paneer  made from 5.0 to 6.0% fat milk (Bhattacharya et al.  1971 ).  Paneer  made from milk standardized to even 3.5 and 5.0% fat has been reported to yield good body and texture. Skim milk yields a very hard bodied  paneer . Sensory score of  paneer  decreased with an increase in the strength of citric acid solution for a specific heat treatment meted to milk (Rao et al.  1984 ). Sachdeva et al. ( 1991 ) observed that the addition of 0.08% calcium chloride to cow milk encouraged the development of  paneer  with compact, sliceable, firm, cohesive body and a closely knit texture. Use of sodium alginate or pregelatinized starch did not help in improving the quality of the filled  paneer  (Roy and Singh  1994 ).

14. Packaging Paneer  being a perishable commodity is highly susceptible to physicochemical and microbiological changes. Therefore, its packaging must provide protection against these damages while maintaining its quality, sales appeal, freshness and consumer convenience. Various packaging materials utilized for packaging of  paneer  include polythene sachets, coextruded films, laminates, parchment paper etc. Most of the  paneer  produced in organized sector is packaged in polyethylene bags because of its better barrier properties in respect of loss of moisture. These bags prove to be a superior packaging material for  paneer  compared to vegetable parchment paper (Rao et al.  1984 ). Packaging of chemical preservatives treated  paneer  with and without vacuum extended its shelf life up to 35 and 50 days, respectively at 8 °C (Singh and Kanawjia   1990 ). Vacuum packaging of cow milk  paneer  is reported to have enhanced its shelf life from 1 week to more than 30 days at 6 °C (Sachdeva and Prokopek   1992 ).  Paneer  packaged in high barrier film (EVA/EVA/PVDC/EVA) under vacuum and heat treated at 90 °C for 1 min had a shelf life of 90 days under refrigeration. Rao et al. ( 1984 ) prepared  paneer  from standardized buffalo milk having 6% fat and packaged in polyethylene and vegetable parchment paper and then stored at 6–8 °C. They found that decrease in moisture content of  paneer  was more in the samples packaged in vegetable parchment paper than in polyethylene. The titratable acidity was also found to be slightly more in parchment paper packed samples than in other packaging materials.

15. Shelf life A relatively shorter shelf life of  paneer  is considered to be a major hurdle in its production at commercial level. It cannot be stored for more than 1 day at room temperature in tropical countries. Bhattacharya et al. reported that  paneer  could be stored for only 6 days at 10 °C without much deterioration in its quality, though the freshness of the product was lost after 3 days. It has been noticed that the spoilage in  paneer  occurs due to growth of microorganisms on the surface. A greenish yellow slime formation on the surface of  paneer  and the discolouration is accompanied with off flavour . Therefore, efforts have been made to curb the surface growth of microorganisms and thereby increase the shelf life of  paneer . Dipping of  paneer  in brine solution may increase the shelf life of  paneer  from 7 days to 20 days at 6–8 °C ( Kanawjia and Khurana  2006 ). Arora and Gupta ( 1980 ) reported that during storage at −13 °C or −32 °C for 120 days, moisture content tended to decrease, non-protein nitrogen increased and significant changes in fat, total nitrogen content and pH occurred. Storage of  paneer  at these temperatures did not affect the flavour and appearance significantly but body and texture was deteriorated.

16. Defects Causes Prevention 1. Flavour  Sour Use of stored milk having high titratable acidity. Use fresh milk having no developed acidity. Addition of excess amount of coagulating agent. Use proper amount and concentration of coagulating agent  Smoky Use of smoky fire for heating the milk Use non-smoky fire for heating the milk.  Rancid/oxidized Hydrolysis of fat by lipase enzyme or oxidation during storage at room temperature Store the  paneer  at 4 °C.  Stale Storage of  paneer  at low temperature for longer duration Ensure quick retailing and maintain the temperature up to 4 °C 2. Body and texture  Hard body Low fat: SNF ratio in milk Use fresh milk. Standardize fat: SNF ratio to 1:1.65 Excessively high coagulation temperature. Coagulate the milk at 70 °C.  Coarse texture Use of highly acidic milk. Use fresh milk having normal acidity (0.12–0.14%). Inadequate fat content in the milk. Use milk having optimum fat content. High coagulation temperature. Coagulate the milk at optimum temperature. Too low pH of coagulation Use optimum pH of coagulation (5.3). 3. Colour and appearance  Dry surface Higher fat percentage in the milk used. Optimize or lower the fat content of milk.  Surface hardening Paneer  exposed to atmospheric air for longer duration Do not expose the  paneer  in atmospheric air for longer duration Pack the  paneer  in good moisture barrier packaging material.  Visible dirt/foreign matter Improper straining of milk. Correct straining of milk Utensils not cleaned properly. Use properly cleaned utensils. Handling or transport of  paneer  in unhygienic manner Adopt hygienic measures during handling or transport of milk.  Mouldy surface Storage of  paneer  under humid condition. Maintain the humidity of storage chamber. Excessive moisture content in  paneer . Early disposal/marketing of  paneer . Optimize the moisture content in the  paneer .

17. Paneer  represents a variety of Indian soft  cheese , which is used as a base material for the preparation of a large number of culinary dishes and is highly nutritious and wholesome. Most of the  paneer  is produced in unorganized sector in very small quantities using traditional methods. Reluctance to use modern technological processes has hampered the organized production, profitability and export performance of  paneer . Recently some of the organized dairies have taken trials to produce  paneer  in continuous machines on commercial scale. Shelf life limitation is a major constraint for its large scale production as it is spoiled within 2 days at room temperature or 7–10 days under refrigeration. Use of antimicrobials and natural antioxidants and vacuum packaging of  paneer  in nylon pouches reasonably increased the shelf life and facilitated distribution and marketing of product.