Pet food is available in dried, semi-moist and wet forms. Dried pet food usually has a moisture content below about 10% by weight and is usually prepared by extrusion cooking. In general, a starting mixture containing cereals and perhaps meat and bone meals is moistened and fed into an extruder. In the extruder, the mixture is subjected to more or less complete cooking. The cooked mixture is then extruded through a shaping die and cut into pellets. The pellets are then dried to a desired moisture level. Flavours may then be coated onto the pellets in order to improve palatability. The pellets may then be fed to pets in this form.

The substantially standard, invariable form of dried pet food has caused it to suffer from consumer fatigue. To combat this, many attempts have been made to add variety to these foods. For example, different colouring and flavouring agents have been incorporated into the starting mixture. The pellets obtained may then be mixed to provide a pet food in the form of pellets of various colours and flavours ; each pellet having a single colour and flavour.

In a further development of this, Canadian patent 1, 230, 005 describes a process in which the cooked mixture is separated into two streams and a different colouring or flavouring agent is added to each stream. The streams are then recombined to provide a pet food in which the individual pellets each have two colours or flavours.

In a separate issue, dried pet foods often form fines during storage.

Moreover, the flavours coated onto dried pet foods often cause the pellets to be greasy to the touch. These factors also detract from consumer acceptability.

Therefore there is a need for further varieties of dried pet foods to combat consumer fatigue, which have reduced susceptibility to form fines, and which are less greasy to the touch.

Accordingly, in one aspect, this invention provides a dried pet food in the form of a pellet, the pellet comprising a core of a thermally gelatinised starch matrix and an outer, dry glossy coating.

The dry, glossy coating provides the advantage that the pet food is less greasy to the touch. Further, there is reduced susceptibility to form fines and an

attractive appearance. Further, it is surprisingly found that the pet food is extremely palatable to pets.

Preferably, the glossy coating provides a mean reflectance of the top 5% of reflectance scores which is at least about 60% of the maximum standard high gloss score. More preferably, the mean reflectance of the top 5% of scores is at least 70%, for example at least 75%, of the maximum standard high gloss score.

In another aspect, this invention provides a dried pet food in the form of a pellet, the pellet comprising a core of a thermally gelatinised starch matrix and an outer saccharide-based coating, the outer coating providing the pellet with a glossy appearance.

Preferably the dried pet food has a moisture content of less than about 10% by weight. Further, the outer coating preferably comprises about 1% to about 10% by weight of the dried pet food. The outer coating may comprise corn syrup.

In another aspect, this invention provides a process for preparing a glossy, dried pet food, the process comprising : thermally gelatinising a starch source for providing a gelatinised starch matrix ; forming the gelatinised starch matrix into pieces ; drying the pieces ; and coating the dried pieces with a saccharide-based solution ; and drying and polishing the pieces.

Detailed Description of Preferred Embodiments of the Invention Embodiments of the invention are now described, by way of example only.

In this specification, the term"pellet"means a piece of a size suitable to be fed to a pet, irrespective of the shape.

The invention is a dried pet food in the form of pellets which have a glossy, dry, preferably saccharide-based, coating. The coating provides the pellets with a glossy appearance which is attractive to the eye. Further, the coating reduces the formation of fines and is dry to the touch.

The dried pet food is produced by cooking a feed mixture, forming the cooked mixture into pellets, drying, and then coating the pellets with the glossy coating. The cooking and forming steps are preferably carried out using an

extruder. However, the pellets may be produced by other cooking procedures such as baking.

The feed mixture is preferably made up of carbohydrates, protein and lipids.

Suitable sources of carbohydrates, protein and lipids are well known in the art.

For example, suitable sources of carbohydrates include grains, such as corn, rice, wheat, barley, oats, and mixtures of these grains ; beets, and soy flour. Usually the carbohydrate source will include starch which is thermally gelatinisable.

Pure or substantially pure starches may also be used if desired. The exact carbohydrate source or sources used is not critical to the invention. The dried pet food conveniently contains about 20% to about 65% by weight of carbohydrate.

Suitable sources of protein include vegetable and animal protein sources.

Suitable vegetable protein sources are gluten, wheat protein, soy protein, rice protein, corn protein, and the like. These proteins may be provided in the form of flours, concentrates and isolates as desired. Suitable animal protein sources are muscular or skeletal meat of mammals, poultry, and fish ; meals such as meat meal, bone meal, fish meal, and poultry meal ; by-products such as hearts, liver, kidneys, tongue and the like ; and milk proteins. The dried pet food conveniently contains about 12% to about 50% by weight of protein. Of course, the source of carbohydrate may also be a protein source ; and vice versa.

Suitable lipid sources include animal and vegetable fats such as tallow, sunflower oil, safflower oil, corn oil, soybean oil, and the like. The choice of the ingredients making up the feed mixture will be largely determined by the nutritional needs of the animal and palatability considerations.

The feed mixture may include various other ingredients, for example, salt, spices, seasonings; vitamins; minerals, flavouring agents, colouring agents, texture modifying agents, and the like.

In a specific example of a suitable process, a feed mixture is fed into a preconditioner. In the preconditioner, water or steam, or both, is mixed into the feed mixture. Sufficient water or steam is mixed into the feed mixture to raise the moisture content of the feed mixture to about 10 to about 30% by weight. If desired, the temperature of the feed mixture may be raised in the preconditioner to about 60°C to about 90°C by weight. A suitable preconditioner is described in US patent 4, 752, 139.

The moistened feed leaving the preconditioner is then fed into an extruder.

The extruder may be any suitable single or twin screw, cooking-extruder.

Suitable extruders may be obtained from Wenger Manufacturing Inc, Clextral

SA, Biihler AG, and the like. During passage through the extruder, the moistened feed passes through a cooking zone and a forming zone. In the cooking zone, the moistened feed is subjected to mechanical shear and is heated to thermally gelatinise starch components. The maximum temperature is usually above about 100°C and up to about 150°C. The gauge pressure in the forming zone may be selected to about 300 kPa to about 10 MPa as desired. If desired, water or steam, or both, may be introduced into the cooking zone. During passage through the extruder, the starch in the moistened feed is gelatinised to provide a gelatinised matrix.

The gelatinised matrix leaving the extruder is forced through a die. Any suitable die may be used. For example, the die may be as described in US patent 5, 486, 049 ; the disclosure of which is incorporated by reference. If desired, colouring, flavouring or texturising agents, or mixtures of these agents, may be injecte into the gelatinised matrix in the die.

Upon leaving the die, the extrudate is cut into pieces using blades in the usual manner. The individual pieces may then be dried and, if desired, coated with further flavouring agents. After drying, the pieces preferably have a moisture content of less than about 10% by weight ; for example about 3% to about 7% by weight.

The pieces are then transferred to a suitable coating apparatus. Tumble coaters are particularly suitable since the pieces are less susceptible to breakage.

However, other coating apparatus such as fluidised beds or screw coaters may also be used.

In the coating apparatus, the pieces are coated with a suitable solution for providing a glossy appearance and, if desired, increased palatability. The solution is conveniently a saccharide-based solution. The solution may also contain flavours or a flavour system. After coating, air is blown into the coating apparatus to dry and polish the pieces as they are being tumbled. The air may be at ambient temperature or may be heated. This provides the individual pieces with a shiny, saccharide based coating. Any suitable saccharide source may be used to produce the saccharide-based coating. Suitable examples include corn syrup, maltodextrin, sucrose, and the like. Corn syrup is particularly preferred.

Air may be directed into the coating apparatus to dry the pieces as they are being coated. The air may be at an ambient temperature or may be heated.

The amount of the saccharide-based solution which is sprayed onto the pieces is preferably selected such that the saccharide provides less than about

10% by weight, on a dry bases, of the coated pieces. Preferably the saccharide provides less than about 9% by weight, on a dry bases, of the coated pieces ; for example about 3% to about 8% by weight.

The dried coated pieces are removed from the coating apparatus to provide the dried pet food in pellet form. After a short holding time to allow moisture and temperature to equilibrate, the pieces may be packed into suitable packages.

The pellets have a moisture content of less than about 10% by weight ; for example about 3% to about 7% by weight. Further, the pellets have an attractive glossy appearance with a surface which is dry to the touch. The pellets are not greasy. It is also surprisingly found that the pellets have good palatability when fed to pets despite the fact that some of the flavours which are attractive to the pets are encased by the saccharide-based coating.

Specific examples are now given for further illustration. In the examples, all reflectance measurements are made using a Tricor Gloss Meter in accordance with manufacturer's instructions. The mean score of the top 5%, 10%, 25% and 50% scores is computed. A score of 0 indicates no gloss whatsoever while a score of 268 is the maximum standard high gloss score. In general, the human eye focuses on the top 25% of scores ; more-usually on the top 5% of scores.

Hence if the top 5% of scores are high, a human will consider the object to be very shiny or glossy.

It is generally accepted that a top 5% of scores : - - from 0 to 100 is considered non-glossy ; - from 100 to 200 is considered glossy ; and - above 200 is considered highly glossy.

Example 1 A milled mixture made up of rice, poultry meal, corn gluten, corn meal, salts, vitamins and mineras, is fed into a preconditioner. A chicken digest and tallow is fed into the preconditioner along with the milled mixture. The preconditioner is operated at about 90°C. Steam and water are injected into the preconditioner.

The moistened feed leaving the preconditioner is then fed into a model X165 single screw-extruder obtained from Wenger and gelatinised. The feed is heated to a temperature above about 100°C in the extruder.

The gelatinised matrix is forced through a die as described in US patent 5, 486, 049 and cut into pieces of about 3 to about 5 mm length. The pieces are then coated with flavouring agents and dried in the normal manner.

The dried pieces are then transferred to a tumble coater. A corn syrup- based solution, which contains about 60% by weight of corn syrup and is at a temperature of about 93°C to about 99°C, is sprayed on the pieces in the tumble coater. The solution also contains flavour. The weight ratio of corn syrup-based solution to dried pieces fed into the tumble coater is about 1 : 9. After coating, air at ambient temperature and low relative humidity is blown into the tumble coater to dry the pieces as they are being tumble polished.

The coated pellets are then collected. The coated pellets have a moisture content of about 6. 5% by weight and a shiny, dry coating which is not greasy or sticky to the touch. The coating comprises about 7% by weight, on a dry basis, of the pellet.

The reflectance of the pieces is then measured. Pieces produced in exactly the same way but with a standard chicken digest flavour coating are used as control. The results are as follows : Control Example 1 Mean score Mean score Top 50% 69146 Top 25% 77170 Top 10% 86190 Top 5% 92 201 The control pieces have essentially no gloss while the pieces of example 1 have a very high level of gloss, based on the top 5% of scores.

Example 2 Three group of 25 to 27 healthy cats per group are used in the trial. Cats which are known to readily consume both canned and dried foods are selected.

During the trial, the cats have ad libitum access to water and are fed a meal of fresh dried food once daily.

The cats are presented a choice of two dried pet foods in pellet form. Dried food A is the control food of example 1. Therefore the final coating for dried

food A is a flavour coating. Dried food 1 is the food produced according to example 1 with the saccharide-based coating. The amount of each dried pet food consumed by each cat is monitored over the extended meal time. The trial is repeated twice again ; once with the same pet foods which have been stored for 45 days ; and once with the same pet foods which have been stored for 90 days.

Statistical analysis indicates that the cats significantly prefer Food 1. The confidence level is 95%.

Example3 Two dried pet foods in pellet form are filled into bags. Dried food A is the control food of example 1. Dried food 1 is the food produced according to example 1 with the saccharide-based coating.

The bags are shaken and then stored for a month. During storage, the bags are moved once a day in order to simulate normal conditions in the supply chain.

The bags are then opened and visually inspected for the formation of fines. The bags containing dried food 1 contain noticeably less fines.