Background Art In addition to a steadily increasing worldwide demand for fresh kiwifruit (Actinida deliciosa var deliciosa), there is a potentially large international market for processed kiwifruit containing food products. To a large extent, this market does not exist now owing to the difficulty in producing products that retain the desirable aroma and green colour which characterize fresh kiwifruit. Thus, the prior art teaches that kiwifruit may be pulped and stored essentially unchanged if held at a temperature of -18°C. Under these conditions, the pulp remains stable for a period of about 3-12 months.

Although this process is practised commercially, one obvious deficiency is the cost of maintaining and transporting the pulp at such a low temperature.

A further deficiency is that whilst freezing is an effective preservative measure, the proteolytic enzymes present in the pulp are not destroyed. Preservation by freezing also has no effect on the acid concentration in the pulp. Thus, given that chlorophyll is unstable at the acid pH levels present in the pulp, freezing will not arrest the loss of colour. Other fruit processing techniques which utilize pasteurization and evaporative concentration treatments are also unsatisfactory as in the presence of acid the necessary elevated temperatures degrade chlorophyll and alter the aroma. Furthermore, avoidance of heat does not assist the stability of chlorophyll owing to the relatively high acid levels.

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Recognizing these difficulties in the prior art and the potential for a large market in processed kiwifruit food products, the present inventors have surprisingly found that it is possible to produce such products whilst substantially avoiding the prior art deficiencies.

Disclosure of the Invention In essence, the present inventors found that, if a chlorophyll containing fraction was separated from the pulp using a largely mechanical process, the pulp could be treated separately by preferably removing an aroma-containing fraction prior to subjecting the juice to conventional processing and the residual pulp to a preservative treatment. These fractions could be stored for long periods prior to them being combined and incorporated into appropriate food products.

Accordingly, in a first aspect, the present invention consists in a process for the preparation of kiwifruit fractions for use in the preparation of kiwifruit products, comprising forming kiwifruit into a pulp; treating the pulp to form a chlorophyll containing fraction, a juice fraction a residual pulp fraction; and subjecting the residual pulp fraction to a preservative treatment.

In a second aspect, the present invention further consists in a process for the preparation of a kiwifruit product comprising forming the kiwifruit into a pulp; treating the pulp to form a chlorophyll containing fraction, a juice fraction and a residual pulp fraction; subjecting the residual pulp fraction to a preservative treatment and combining the chlorophyll fraction with the juice fraction and/or the residual pulp juice fraction.

In a third aspect, the present invention still further consists in a food product which includes a chlorophyll fraction and optionally a kiwifruit fraction selected from the group consisting of a juice fraction and

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a residual pulp fraction.

In a fourth aspect, the present invention still further consists in a kiwifruit product comprising a kiwifruit derived chlorophyll fraction and optionally a kiwifruit fraction selected from the group consisting of a juice fraction and a residual pulp fraction.

The major advantage of the processes of the invention is that firstly, the chlorophyll and juice fractions are removed from the acid environment and are not subjected to a preservative. treatment in an acid environment such as pasteurization, both of which act to destroy the chlorophyll and aroma components in the juice fraction. Furthermore, if pasteurization is used, the endogenous proteolytic enzymes are destroyed. A number of means may be used to form the kiwifruit into a pulp, of which the most preferred is to pass the kiwifruit through a hammer mill. Following pulping, the seeds, skins and coarse fruit pieces may be removed from the pulp. One means of accomplishing this is a brush finisher.

After removal of these materials, a number of sieve stages may be used to remove a coarse pulp and a fine pulp. The remaining material is subjected to a separatio to yield a chlorophyll containing fraction and a juice, substantially devoid of chlorophyll. Such a separation may be conveniently effected by centrifugation in which case a clear juice will result and the chlorophyll will b present in the sediment. Although the chlorophyll sediment could be used in that form, desirably the sediment is neutralised and washed to remove water solubl components. As the sediment has a pH of about 3 - 3.5, preferably it will be neutralised to a pH of about 5 - 7.

For long-term storage, preferably the resultant chlorophyll fraction is freeze-dried or otherwise preserved to give a storable product.

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In a preferred embodiment, an aroma-free juice fraction and an aroma-containing fraction are formed by extracting the chlorophyll free juice. If subjected to prior sieving stages, the resultant coarse and fine residual pulps may also be extracted.

A variety of extraction processes well known in the art may be used.

Once the aroma-containing fraction has been formed, it may be subjected to a concentration process to form an aroma essence.

Once the aroma-free juice fraction is formed, it may be subjected to conventional juice processing to produce a base suitable for food usage.

The residual pulp remaining after juice processing is subjected to a preservative treatment, such as pasteurization and drying.

Modes for Carrying Out the Invention A typical embodiment of the invention will now be described with reference to the diagram, on the page following, which is a flow diagram indicative of the principal steps in the process.

A pulp prepared by treating kiwifruit in a hammer mill is passed through a brush finisher to separate coarse material, such as seeds, skin fragments and large pieces of tissue, from the juice released from the fruit cells. The juice is then freed from the fruit tissue by serial passage through fine sieves and centrifuged to produce a clear juice and a green, chlorophyll-rich sediment. The chlorophyll sediment is neutralized and soluble constituents are eliminated by washing with water, after which the sediment is freeze-dried to produce a storable powder.

The clear juice from centrifuging is passed through an extraction column to obtain an aroma-free juice and an aqueous aroma extract. The aroma component is adsorbed

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from the latter onto a resin from which it is extracted with alcohol to yield a concentrated essence.

The aroma/chlorophyll-free juice is then processed conventionally, such as by enzymic treatment followed by pasteurization and evaporation to form a stable kiwifruit juice base.

It is to be understood that other portions of the fruit, eg, seeds, may also be recovered.

In an example of the application of the above process, 60kg of kiwifruit was treated using the above process to yield 60g chlorophyll powder, 50ml concentrated essence containing 0.8% aldehyde as hexenal and 42kg juice. The chlorophyll fraction, aroma-free juice, aroma-containing fraction and other fractions from a process such as described above may be recombined in various proportions to give a range of attractive kiwifruit products. Examples of a number of processed food products of the invention are set out below. Thus a sorbet may be prepared by mixing the components with gums and emulsifiers in a scraped-surface heat exchanger-type ice cream maker set to -3°C, as follows: Example 1

A sorbet was prepared by combining chlorophyll powder and aqueous aroma extract with sufficient sucrose to make a slurry. Dried kiwifruit pulp, a whipping agent (Versa whip 520) and a gum (Supercol g.f.) were thoroughly dispersed in kiwifruit juice and the sucrose slurry and kiwifruit seeds mixed in; sufficient sucrose was added t make the final concentration of soluble solids 24 degrees Brix. The mixture was rapidly frozen in a Taylor Model B343 scraped surface ice confection maker. The product was a soft-serve sorbet of an attractive green colour. Example 2 A kiwifruit ice cream was prepared by mixing 20g

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chlorophyll powder, 70g kiwifruit seeds, 600mL aqueous aroma extract, into 10 litres of a tempered ice cream base. The mixture was quickly frozen in the scraped surface heat exchanger. The product had the soft green colour typical of fresh kiwifruit. Example 3

A cloudy green kiwifruit juice drink was prepared by diluting 4 litres of processed clear kiwifruit juice to 6 litres and dispersing 12g chlorophyll powder and 60g dried residual pulp and sufficient sugar for optimum acceptability into the liquid by means of a Bamix blender. In addition to the food products exemplified above, a variety of other products may be prepared.

For example, a kiwifruit yogurt may be prepared by incorporating the chlorophyll powder, flavour essence and juice into a prepared yogurt. A frozen kiwifruit pulp could be prepared by combining the chlorophyll powder with dried residual pulp, seeds and juice and immediately freezing the mixture. Frozen kiwifruit confections such as fruit bars could be prepared in a similar manner to the frozen pulp but with addition of suitable texture modifiers before freezing.

Whilst the present invention has been described with reference to certain preferred embodiments and examples, it will be recognized that numerous variations and modifications may be made to the invention without departing from the spirit or scope thereof.

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