Paper No.: 07 Paper Title: TECHNOLOGY OF MILK AND MILK PRODUCTS Module 12: TECHNOLOGY OF DAIRY SPREADS Introduction Table butter usually poses problem of spreadability, when butter is used directly from the fridge. Spreadability of butter is one of the convenience factors that are sought after by the consumers of butter. The calorie contribution by Table butter is also quite high; calorie-conscious people want to consume fat containing product, but with fewer calories. Dairy spreads are one solution to such problem. Physical methods to control the variation in butter hardness, and to impart a softer texture have had limited success. The softening achieved may be largely confounded by temperature variations in distribution and the home. Most butters have too high a level of solid fat for easy spreading when cold, and although normally sufficiently plastic to spread at 15 o C, when less than 40% of the fat is solids, easy spreading characteristics are only achieved at solid fat levels of 20-30%. The proportion of unsaturated fatty acids must be substantially increased to make a spreadable milk fat-based product. This can be achieved by adding liquid vegetable oil to the butter or cream to reduce solid fat content, if regulation permits the same. To achieve a spreadable butter at domestic refrigeration temperatures (i.e. 5-10 o C), a substantial modification of the properties of the milk fat is needed. The principal methods used have been modification of the diet of the cow, and the recombination of fractionated milk fat to form butter. FSSAI definition: A Fat Spread is a product in the form of water-in-oil emulsion of an aqueous phase and a fat phase of edible oils and fats, excluding animal body fats. It shall be free from animal body fat, mineral oil and wax. The individual oil and fat used in the spread should conform to the Food Safety and Standards Act (FSSA) standard for that specific oil.
The three groups of fat spread are: 1. Dairy spreads fat content will be exclusively milk fat. 2. Blended spreads fat content will be a mixture of milk fat with any one or more of hydrogenated, unhydrogenated refined edible vegetable oils or interesterified fat. 3. Non-dairy spreads fat content will be a mixture of any two or more of hydrogenated, unhydrogenated refined vegetable oils or interesterfied fat. The fat content shall be declared on the label. In mixed fat spread, the milk fat content shall also be declared on the label along with the total fat content. Vegetable fat spread shall contain raw or refined sesame oil in sufficient quantity, so that when separated fat is mixed with refined groundnut oil in the proportion of 20:80, the red colour produced by Baudouin test shall not be lighter than 2.5 red units of Lovibond scale. The word 'butter' will not be associated while labeling the product. It may contain milk solids not fat. The product shall show a positive test for vitamin A when tested by Antimony trichloride (Carr-Price) reagent. It shall be compulsorily sold in sealed packages weighing not more than 500 g with Agmark certificate mark. It may contain annatto and/or carotene as colouring agents, permitted emulsifiers and stabilizers and sequestering agents. The alternative to modifications of the milk fat itself is to blend the milk fat with other fats that is liquid at 0-5 o C. Such method can reduce the cost of product too and can make the product healthier too (low saturated fat, low cholesterol). However, mixing of milk fat with other fats is not permitted in countries like Germany, Netherlands and Denmark. Formulation of fat spread The typical formulation of a fat spread is furnished in Table 2. The formulation includes fat source (milk fat or vegetable oil/fat or combination of both), source of milk protein, salt, colouring, flavouring, water, emulsifier, stabilizer and may contain antioxidant and sequestering agent too.
Table 1. Specifications for Fat spread as per FSSA Parameter Content Fat Moisture Salt Starch Diacetyl (flavouring agent) Antioxidants (BHA or TBHQ) Sorbic acid and its Na, K & Ca salts or Benzoic acid and its Na, K salts, singly or in combination Melting point of extracted fat (Capillary slip method) for Vegetable fat spread Synthetic vitamin A at time of packing (for Vegetable fat spread) Unsaponifiable matter of extracted fat Minimum 40%, maximum 80% by weight Minimum 16%, maximum 56% by weight Maximum 2% by weight in aqueous phase Minimum 100 ppm, maximum 150 ppm Maximum 4 ppm Maximum 0.02% of fat content of spread Minimum 1000 ppm by weight Max. 37 o C Min. 25 IU/g Milk fat and mixed fat spread Max. 1% by weight Vegetable fat spread Max. 1.5% by weight Acid value of extracted fat Max. 0.5% * ppm parts per million Role played by ingredients in fat spread Milk fat and/or Vegetable oil/fat: Any type of fat chosen will determine the spreadability of fat spread based on its inherent degree of saturated or unsaturated fatty acid content. Hence, judicious blending of fat is an important step; hydrogenation of interesterification of fat is another possibility to determine the spreadability and stand-up property of fat spread.
Protein source: Usually milk protein is included in low-fat spreads to confer solids and body to the fat spread. Normal skim milk solids (i.e. Skim milk powder) are used; use of butter milk concentrate or butter milk powder is a viable alternative. Common salt: Use of NaCl helps to confer the salty taste as well as a positive impact on the shelf life of resultant fat spread. The level of salt used is about 1.0-1.5% by weight. Colouring matter: The same natural colouring matters as used for Table butter (i.e. annatto, β- carotene) may be used to impart the desired shade of yellow colour to fat spreads. Stabilizer and emulsifier: Stabilizers like guar gum, locust bean gum, modified starch etc. can help to impart body especially to low fat spreads, where the contribution of fat to body is low. Stabilizers may be used at levels of 0.15-0.30% by weight of spread. The stabilizers can help in preventing wheying-off in such products. Emulsifiers like mono and digylcerides of fatty acids, lecithin, etc. helps to mix the two otherwise immiscible phases water phase and fat phase. The emulsifier may be used at levels of 0.1-0.2% by weight. Antioxidants: Antioxidants like butylated hydroxyl anisole (BHA), tertiary butyl hydroquinone (TBHQ), etc. can be especially used in vegetable fat based spreads at levels of 0.01-0.02% by weight, if PUFA based vegetable oils have been used. Sequestering agent: Sequestering agent like citrate salts or even proteins may be used that can chelate metal ions like Cu or Fe to avoid oxidation of fat in vegetable fat based spreads. Water: Since low-fat spreads have higher moisture content, water is required to be used to standardize the fat content of spread. However, when milk, skim milk, buttermilk are used as milk solid source, the contribution of water by them is required to be taken into consideration.
Table 2. Typical formulation of fat spreads Ingredients Dairy blend (80% fat) (%) Low fat spread Butter-based (%) Blend based (%) Butter fat 60 40 16 Vegetable oil 20-24 Milk protein/caseinate 1.5-2.0 5-7 5-7 Water 16 to 100 to 100 Salt 1 1 1 Emulsifier 0.1 0.6 0.6 Flavour/Colour + + + Processing steps for Fat Spread manufacture The manufacture of fat spread entails the following six steps: 1. Preparation of aqueous phase and fat phase separately or as a mixture. 2. Coarse emulsification of the phases. 3. Cooling in a Transmuter. 4. Working in a Texturizer/Pin-worker. 5. Setting in crystallizer. 6. Filling and packaging. Production of fat spread Production of spreads with good plastic properties at refrigerator and room temperatures is achieved with the use of scraped-surface heat exchanger (SSHE). A SSHE is typically a tubular heat exchanger cooled by a liquid refrigerant (i.e. ammonia) with scraper blades mounted on a central shaft that rotates continuously, removing crystallized fat from the inner tube surface to promote rapid cooling and crystal nucleation in a short residence time (seconds). SSHE units
usually are employed in combination with crystallizer units, which hold a larger volume and have a longer residence time (several minutes). These units work the product between a series of metal pins fixed within the crystallizer tube and others mounted on a rotating central shaft, shearing the product, preventing formation of large crystal networks, and dispersing moisture droplets. The majority of crystallization of the fat takes place in the crystallizer unit(s) and the blend may then be transferred to resting tubes to continue crystallization, although with less shear, before packing. Examples of commercially available fat spreads Several commercial firms are preparing fat spreads. Few examples include Amul Lite by Amul Dairy, Anand, India; Promise by Unilever, USA; Bexlight by Walter Rau, Germany; Bregott by Swedish dairies board; Latt and Lagom by Swedish dairy company Mjolkcentralen, Clover by Dairy Crest, UK, etc. The details of a few well known fat spreads are given below. I. Bregott A good example of a dairy spread is Bregott, developed and marketed by the Swedish Dairies Board. Bregott was originally developed using ripened cream (35% fat, ph 4.6-4.7) to which refined, deodorized soybean oil was added to the batch butter churn. The traditional dairy blend such as the Swedish product Bregott, launched in 1976, was prepared by injecting vegetable oil, usually canola, soybean or rapeseed, into the cream prior to churning in a continuous butter maker. Since the blend of milk fat and vegetable oil is softer and more spreadable at refrigeration temperatures than butter, it was necessary to churn the cream and oil mixture at a lower temperature (i.e. 5 C). A continuous method was subsequently developed using a PSM butter maker. The final product typically has a fat content similar to butter but with 15 to 25% of the milk fat replaced by vegetable oil. The product is packed into tubs, as the butterfoil cannot provide sufficient support to such soft product. II. Clover
Clover is a mixed fat spread (72% fat) that was launched by Dairy Crest in UK in 1982. The method used a blend of non-dairy fats (soyhean oil, more saturated fat and a monoglyceride emulsifier such as Dimodan S), with pasteurized sweet cream. The nondairy fat should have a solid fat content (SFC) of 15.0-35.0% at 5 o C and 7.5-25.0% at 20 o C e.g. a blend of soybean oil and partially hydrogenated soybean oil. The fat addition level of vegetable fat was kept less than 50% of the total fat in order to maintain the dairy claim. The inclusion of some form of hard fat provided a solid base that improved the product s body and reduced oiling off at room temperature. Clover could be made by two methods (i) continuous buttermaker, and (ii) using margarine technology. Clover had slightly higher (20%) moisture content than butter (< 16%) and to aid dispersal of the moisture an emulsifier is added to the vegetable oil/buttermilk mixture. Such dairy and vegetable fat blend had a SFC of 42% at 5 o C and 12% at 20 o C. III. Latt och Lagom A reduced fat protein-enriched spread product named Latt och Lagom (L & L) was developed by the Swedish dairy cooperative. The objective was to produce a spreadable product with half the fat of butter or margarine, while using dairy products as the principal ingredients; regulation requiring 39.0-41.0% fat for low-fat spreads in Sweden. L & L utilized aqueous phase comprising of concentrated buttermilk, which was dispersed in a lipid phase comprising of milk fat (AMF), soybean oil and monoglycerides (0.3%). The aqueous phase may be as high as 60.0% compared to 16.0% for butter. Milk fat is used as the principal fat. In preparation of L & L, pasteurized cultured buttermilk (ph 4.6) is passed through a nozzle bowl separator to obtain a buttermilk protein concentrate ( > 13.0% protein). Such concentrate is then treated with sodium citrate and sodium phosphate to raise the ph and sequester calcium from the casein. Other additives include NaOH for ph adjustment, salt for taste and preservative like potassium sorbate, -carotene for colouring and vitamins A and D. Aroma compounds may also be added. A protein level of 13% in concentrated buttermilk provided 8.0% protein in fat spread. The emulsion is formed by adding the aqueous phase (45 o C) to the lipid phase (50 o C). The combined emulsion is then pasteurized and
cooled (35-40 o C, then to 8-12 o C) using SSHE and worked (using a pin worker unit). The cooled emulsion is piped direct to the filler for dosing into plastic tubs. Conclusion Continuous manufacturing procedures are already available for these dairy products; however, adoption of such technology by the Indian dairy plants is to a very limited extent due to the exhorbitant cost and relying a lot on some imported machinery. Due to the changing diet pattern of the consumers owing to the greater prevalence of Coronary Heart Diseases, Obesity, etc. people are now shifting from fat-rich dairy products to low-fat spreads/dietetic dairy products. There are unlimited options in formulating a fat spread, be it in terms of type of emulsion, flavour, texture, spreadability, calorie, etc.