GB2290449A

GB2290449A - Cooling baked products

Info

Publication number: GB2290449A
Application number: GB9410888A
Authority: GB
Inventors: Richard Sloan
Original assignee: Allied Bakeries Ltd
Current assignee: Allied Bakeries Ltd
Priority date: 1994-05-31
Filing date: 1994-05-31
Publication date: 1996-01-03
Also published as: GB9410888D0

Abstract

To reduce the weight loss of baked products which are vacuum cooled after leaving the baking oven, the baked products 1 are sprayed with liquid, preferably sterile water, by spray nozzles 7; 26 in a cooling prechamber and/or in the vacuum cooler 13 prior to exiting the vacuum cooler 13. The sprayed liquid is absorbed by the baked products 1 to at least partially compensate for the reduction in weight due to the loss of moisture during cooling.

Description

Cooling Baked Products The present invention relates to a method of cooling baked products, especially but not necessarily exclusively cooling loaves of bread, upon removal from the baking oven. The present invention also relates to an apparatus for cooling baked products.

There is well known in the art a method of and apparatus for cooling bread in which the hot baked loaves are conveyed from the baking oven to the cooler, and cool humidified air is then blown over them. The cooled humidified air cools the bread directly, and also causes water within the loaves to evaporate which enhances the cooling effect, but the loss of water from the products results in a reduction in the weight of the loaves of bread which is undesirable. This weight loss can, however, be kept to an acceptable level by controlling the humidity of the air and the rate of cooling, e.g. by controlling the temperature and humidity of the cooling air.

The above cooling process has several disadvantages. The cooling must be gradual and therefore takes a long time e.g. of the order of 2 hours for typical loaves of baked bread, which contributes significantly to production time and hence production costs. The apparatus needed is very large and therefore demands considerable space within a bakery, and operating costs are relatively high. Furthermore, in the design of such a cooler, it is very difficult to achieve the desired level of hygiene and the effective cleaning of such a unit is also very difficult.

There is also known a method of cooling baked products by so-called vacuum cooling. Hot baked products are taken from the oven and introduced into a chamber which is sealed and the air inside the chamber is evacuated. The drop in pressure around the hot baked products causes rapid evaporation of water from the products and they are cooled very quickly. The process is very much quicker than the blown air method mentioned above, and the cycle time for many baked products can be just a few minutes. A vacuum cooling plant has the added advantage of a much smaller space requirement than a blown air cooler while the initial capital costs of the apparatus are not significantly different.

Although vacuum cooling is utilised for cooling various baked products, it has not gained any acceptance in the baking industry for cooling loaves of bread, except for certain types of loaf, such as malt bread loaves which tend to be produced at relatively low volumes. The reason for this is that a relatively large volume of water is removed from each loaf and hence there is a substantial weight loss (approximately 50 grams from an 800 gram loaf of bread). Also, the removal of the moisture from the loaves causes the crust to dry out, making it very hard and brittle, with the result that the crust tends to shatter or fragment if attempt is made to slice the loaf soon after it exits from the vacuum cooler.While the problem of crust dryout and slicing can be alleviated by allowing loaves to stand under ambient conditions for a couple of hours or so before slicing, so that some moisture can be reabsorbed to soften the crust, this "standing time" and the bakery space need to accommodate the bread during standing negates the benefits of the vacuum cooling process over the blown air process.

In any event the main disadvantage of the large weight loss suffered with the vacuum cooling method remains. For these reasons bakeries have continued to use the blown air cooling technique for bread, even in bakeries where vacuum coolers are installed for cooling other baked products.

According to the present invention, there is provided a method of cooling baked products, wherein the temperature of the hot baked products is reduced by vacuum cooling, moisture being lost from the products during the vacuum cooling, and wherein liquid is added to the products to at least partially compensate the moisture lost during cooling.

There is further provided an apparatus for cooling baked products, comprising a vacuum cooler including a chamber and means for evacuating the chamber for reducing the temperature of the hot baked products by drawing moisture from the products, and liquid supply means for adding moisture to the products before the products exit the vacuum cooler.

The invention is based on the realisation and recognition that the moisture loss during vacuum cooling can be effectively compensated for by adding liquid to the products, either immediately before or at the end of the vacuum cooling cycle. Thus, loaves can be cooled without suffering unacceptable levels of weight loss and can exit the vacuum cooler with the product crust sufficiently soft and moist to enable the loaves to be sliced and packaged immediately, thereby dramatically reducing production time. Thus, all the advantages associated with vacuum cooling, including reduced space requirement of the cooling plant, can be attained in the cooling of bread while the hitherto attendant disadvantages of the same are avoided.

In order that the invention may be well understood, there will now be described some embodiments thereof, given by way of example, reference being made to the accompanying drawing in which Figure 1 is a schematic diagram of part of the production line for cooling baked products.

In a process for cooling baked products, specifically baked bread, hot 800 gram loaves of baked bread 1 are carried out of a baking oven 2 by a conveyor belt 4 to a cooler pre-chamber 3 which as shown is a separate spray chamber. On exit of the oven, the loaf core temperature is approximately 96"C and the hot loaves 1 lose a few C between exit of the oven 2 and entry into the cooler pre-chamber 3. A supply pipe 6 feeds liquid, preferably sterile water, to spray nozzles 7 within the cooler pre-chamber 3 which sprays the sterile water onto the loaves 1, adding 30-50 grams of water to each 800 gram loaf 1 without causing significant cooling of the loaves.

The conveyor belt 4 then carries the moistened loaves 1 through an entry door 12 into the vacuum cooler 13. Once the vacuum cooler 13 is full, the entry door 12 is sealed and the air within the vacuum cooler 13 is evacuated via a vacuum system feed pipe 20, removing moisture from the moistened loaves 1 and cooling them.

The weight lost from each loaf 1 during cooling is in the region of 50 grams and the core temperature after cooling is approximately 30"C.

When cooling is complete, the vacuum must be relieved, for which purpose air is released into the vacuum cooler 13 via an air inlet pipe 21 equipped with a control valve. When the pressure in the vacuum chamber has returned to ambient, the exit door 22 is then opened and the cooled loaves 1 carried out of the vacuum cooler 13 by the conveyor belt 4. The cooled loaves may be immediately sliced and packaged.

It is not essential for water to be sprayed onto the loaves before they enter the vacuum cooler 13 and in an alternative embodiment the spray chamber 3 would be omitted and the vacuum cooler 13 equipped with means for supplying liquid for addition to the loaves.

The loaves 1 could be sprayed with liquid in the vacuum cooler 13 before the pressure is reduced in the vacuum chamber to effect the cooling of the loaves, but in a preferred form of this embodiment the cooling apparatus is adapted to add moisture to the loaves at the end of the cooling cycle to replace at least partially the moisture lost during cooling. For this purpose at the same time as, or immediately prior to the air being admitted to the vacuum cooler 13 via the air inlet pipe 21, liquid, preferably sterile water, is introduced into the cooler through a liquid inlet pipe 24 and is sprayed onto the cooled loaves 1 through spray nozzles 26. The water will tend to evaporate immediately due to the reduced pressure and is absorbed by the cooled loaves 1 as the pressure in the chamber rises, moistening both the crust and the crumb of the loaves, and returning the loaves to approximately the same weight as their oven exit weight.

Modifications to the bread cooling apparatus and method are possible without departing from the scope of the invention. For example, liquid could be added by spraying with liquid before vacuum cooling and at the termination of the vacuum cooling if desired.

Claims

CLAIMS:

1. A method of cooling baked products, wherein the temperature of the hot baked products is reduced by vacuum cooling, moisture being lost from the products during the vacuum cooling, and wherein liquid is added to the products to at least partially compensate the moisture lost during cooling.

2. A method of cooling baked products as claimed in claim 1, wherein liquid is added to the baked products prior to commencement of vacuum cooling.

3. A method of cooling baked products as claimed in claim 2, wherein the temperature of the hot baked products is not substantially reduced by the addition of the liquid.

4. A method of cooling baked products as claimed in claim 2 or 3, wherein the liquid is sprayed onto the products.

5. A method as claimed in any of the preceding claims, wherein liquid is added at the termination of the vacuum cooling.

6. A method as claim in claim 4, wherein liquid is added by introducing liquid into the evacuated space around the products immediately prior to and/or during introduction of air into said space to release the vacuum.

7. A method of cooling baked products as claimed in any of the preceding claims, wherein the liquid is sterile water.

8. An apparatus for cooling baked products, comprising a vacuum cooler including a chamber and means for evacuating the chamber for reducing the temperature of the hot baked products received in the chamber by drawing moisture from the products, and liquid supplying means for adding moisture to the products before the products exit the vacuum cooler.

9. An apparatus for cooling baked products as claimed in claim 8, wherein liquid supply means comprise spray means arranged to spray liquid onto products before entering the vacuum cooler.

10. An apparatus for cooling baked products as claimed in claim 8 or claim 9, wherein the liquid supply means comprise means for delivering liquid into the vacuum chamber.

11. An apparatus for cooling baked products as claimed in claim 10, wherein the means for delivering liquid into the vacuum chamber are operable to deliver the liquid immediately before and/or as air is introduced into the chamber to release the vacuum therein.

12. A method of cooling baked products substantially as herein described.

13. An apparatus for cooling baked products substantially as herein described with reference to the accompanying drawings.