FAT RICH DAIRY PRODUCTS

Module 4. Consumer cream products

Lesson 11
CLOTTED CREAM, FROZEN CREAM, CULTURED CREAM

11.1 Introduction

Clotted cream and cultured creams are essentially used for direct consumption or as topping in salads etc., while frozen cream is generally used for reconstitution purposes as source of fat.

11.2 Clotted Cream (>55 per cent fat)

The traditional process involves batch heating of gravitationally separated cream. The heating process induces rapid fat rise. The fat agglomerates on the surface and protein denaturation also takes place. It is characterized by a thick and spreadable texture, nutty flavor and slightly granular texture. The color varies from a pale to a deep yellow depending on local preference. Clotted cream was, for many years, a farmhouse product and significant quantities are still made on a small scale by traditional process.

Traditional Process

The process in which cows' milk is strained into shallow pans which are left for 6-14 h to allow the cream to rise to the surface of the milk. The milk with cream layer is then heated in the pans over a water bath, and the product is held at a temperature of 82-91°C for 40-50 min. During cooling over a period of 24 h the cream layer forms a solid crust which can be lifted clear of the skimmed milk beneath to yield a product with > 55% fat content and often around 67% fat.

Commercial Process

Two methods of larger-scale manufacture are used for producing two types of clotted cream;

1. Float cream method and

2. Scald cream method

Float cream method

The float cream is made in large, open top vessels often arranged in tiers. This method involves scalding a layer of double cream poured over skimmed milk or whole milk held in shallow trays. The trays have jacketed bottoms which are heated with either steam or very hot water. Over a period of 45-60 min the clotted cream crust develops and the product can then be cooled for 12-18h. The cream hardens and it can then be scooped clear of the milk layer and packaged.

Scaled cream method: In this process mechanically separated cream with >54% milk fat content is used. The cream is poured into aluminum or stainless steel shallow trays to form a layer about 20mm deep and the trays are heated either in a water bath or over a low pressure steam chest. During scalding the cream reaches 77-85°C for 45-70 min, following which the trays are transferred on trolleys to a chilled store to cool the product.

Before packing the temperature of both float cream and Scald Cream should be 4-7°C. Clotted cream may be packed in polystyrene flat-topped round containers, closed with a polyethylene/aluminum laminated foil. Alternatively, it is often packed in square or rectangular, shallow HDPE containers closed with a clear plastic film and inserted into a paperboard sleeve carrying the product information.

11.3 Frozen Cream

Cream which is intended purely for ingredient use where structure is unimportant may be frozen without any special precautions. The objectives of frozen cream are as follows:

* To improve the keeping quality of cream during transportation over long distances

* To store surplus cream for use during shortage. Mainly used by ice-cream manufactures who add sucrose (10 to 15 percent by weight) to cream before freezing to prevent oiling off after thawing

Method

1. Separate and standardize cream to 40-50 percent fat.

2. Cream should be pasteurized at 75-88°C for 15s

3. Cooled to 1°C as quickly as possible before freezing

Freezing may be carried out within containers, on a band to give a sheet or pellets, or by direct contact with liquid nitrogen
Bulk storage of frozen blocks of cream in polyethylene bags may be used for surplus cream that is to be later converted into butter or anhydrous milk fat.
Cream should be frozen as quickly as possible and stored at -18 to -26°C, the lower the temperature better will be keeping quality.

A keeping quality of 2-18 months with an average of about six months can be expected. The shelf-life of the cream will be limited by physical and chemical constrains for that product.

11.4 Cultured (Sour) Cream

Sour cream is mainly used in prepared foods, less often in drinks or beverages. Sour cream is an extremely viscous product with the flavor and aroma of butter milk, but with a fat content of 12-30%, its method of consumption is more similar to that of normal cream. Sour cream is used in a number of meat dishes, vegetable dishes and confectioneries.

Production: A typical schedule for production would involve fortifying/standardization whole milk with cream to give the desired fat content, and then heating the mix to around 80°C for 30 min. Homogenization at 13-14 MPa (minimum) and 60-80°C follows, and then in general increases in pressure or temperature above the minimum tend to improve the consistency of the retail material. After cooling to the inoculation temperature of around 21°C, the cream is mixed with 1-2% of mesophilic butter culture, and incubated at 21°C until an acidity of 0.6% lactic acid has been reached (18-20 h).

On cooling, the sour cream is then ready for packing in cartons prior to dispatch, but care must be taken at this stage to avoid any serious deterioration in viscosity. It is for this reason that some manufacturers incubate the cream in the retail cartons, and certainly this process can give rise to a markedly thicker material.

Fig. 11.1 Flow diagram for manufacture of sour cream