HortResearch scientists are working to find out more about the new grape-sized kiwifruit, Actinidia arguta. Storage and
shelf-life capabilities are important factors in the future marketability of the sweet, bite- sized fruit.
Dr Elspeth MacRae and Linda Boyd have completed a KNZ-funded project to determine if a new arguta selection had similar
storage and shelf-life properties if grown in different environments, and if storage and shelf-life responses were
similar to those of the previous season.
The second objective was to determine the feasibility of harvesting the selection earlier in the season, rather than in
the conventional manner when fruit first become soft. They wanted to find out if such fruit were able to store, have a
good shelf-life and good flavour comparable to fruit harvested in the conventional manner.
Fruit maturity was monitored in vines growing at Te Puke Research Orchard. Once seeds in the fruit were all mature a
subsample of fruit was harvested for storage. The remainder of the fruit from Te Puke, and Nelson, were harvested when
one percent of fruit on the vine were ripe, ie. as in 1998. Fruit were stored for six weeks or eight weeks, followed by
shelf- life determinations at 5 or 20oC. Some fruit were monitored for 12 to 16 weeks storage.
The results confirm the need to harvest this selection when one percent of fruit are soft. Fruit can be stored for eight
weeks at 0oC and have three to four weeks shelf-life at 5oC. Fruit stored in a similar manner to the previous season,
allowing at least eight weeks storage followed by three to four weeks shelf-life, if fruit were held in a chiller or
refrigerator display unit. Pitting was the only storage problem and it was minor.
Fruit from Nelson and Te Puke were similar in storage response. Fruit from the first crop from a commercial orchard in
Nelson softened slightly faster in storage, and to a lower fruit firmness, than the fruit from older vines in research
orchards. Fruit harvested before one percent of the fruit on the vine were ripe (soft) did not store as well, and showed
more storage defects and inferior flavour than fruit harvested when one percent were ripe.
"This means that it will not be possible to harvest fruit while all fruit are hard. Attention will need to be given to
harvesting and handling procedures that can deal with the presence of soft and semi-soft fruit. These procedures are
relatively labour intensive for industry and will need to be better streamlined," said Dr MacRae.
"It is recommended that future work on the selection concentrates on this aspect, and that further arguta selections of
interest be compared for storage behaviour, using it as the benchmark."
ends