A practical non-destructive method for rejection of unripe 'Elstar' apples.
Lieshout, J. G. F.; Roelofs, F. P. M. M.; Jager, A. de;
Acta Horticulturae Year: 1998 Issue: No. 464 Pages: 115-120 Ref: 3 ref.
1998
บทคัดย่อ
Unripe Elstar apples early in the season need to be excluded from the market in the Netherlands in order to avoid a suboptimal start to the marketing season. The existing control system, based mainly on a general release date and a starch degradation criterion, is functioning unsatisfactorily, especially because early orchards are not credited. Over a period of 4 years, samples from 6 orchards varying in earliness were collected weekly, starting 4 weeks before the expected release date and ending 2 weeks after, and divided into 2 samples. One sample was kept for 8 days at room temperature (normal marketing scenario) and subsequently used for sensory evaluation (overall acceptability on a 1-10 scale). The other sample was used for measuring weight, ground colour (a*, b*, L), firmness, starch degradation stage, total soluble solids (TSS) and titratable acidity (TA) at harvest. Multiple regression analysis of characteristics at harvest against taste after 8 days showed that the best possible model
based on such criteria was no better or only slightly better than the best possible model based on the non-destructive characteristics of weight and ground colour. Basic data as well as tests in one year showed the latter to provide the correct decisions >80% of the time compared to ca. 50% with the old starch-based system. The success appeared to be due entirely to an increase in the number of right approvals. Thus, the new system recognizes early orchards and rewards individual growers much better, without significantly increasing the risk of unripe fruits entering the market. In addition it is faster, non-destructive and more objective.