This is a final research report from Hort Innovation’s historical archives. Please note that as these reports may date back as far as the 1990s, the content and recommendations within them may be superseded by more recent research.

What was it all about?

Eating quality is a key driver of consumer demand for apples and all sectors of the apple industry agree that consumption could increase if eating quality was improved. This project investigated the effect of post harvest supply chain factors on eating quality of apples. Project partners were the pack house Batlow Fruit Co-operative and the retailer Coles.

Eating quality of three Australian apple cultivars, which were Fuji, Pink Lady® and Red Delicious, was investigated in relation to three factors in a controlled study:

1. Storage time after harvest; fruit were evaluated at four time points (June, August, November and January). Apple evaluated at the first time point had been recently harvested and air stored. Apples evaluated at subsequent time points were stored in CA atmosphere and were 1-MCP treated.
2. Cooling method; at each time point following washing, sorting, grading and packing, static cooling, which was current best practice, was compared to rapid cooling to bring apples more quickly to optimum temperature for distribution.
3. Storage temperature; apples were subjected to 10 days of storage at either ambient or chilled temperatures.

A trained sensory panel measured the sensory properties of apples in terms of appearance, odour, taste, flavor, texture and mouthfeel. Fruit firmness and total soluble sugar content were measured instrumentally in parallel, and visual assessments were conducted on intact and cut apples.

Visual quality of all apples was good. Each cultivar had distinct sensory properties which displayed variations throughout the year. Rapid cooling provided somewhat better texture and mouthfeel for the air stored apples evaluated at the first time point but had no impact on apples stored in controlled atmosphere and treated with 1-MCP during the remainder of the season.

Loss of eating quality due to ambient storage temperature, when compared to chilled storage, was largest for the recently harvested air stored apples and was less pronounced for apples that were stored in controlled atmosphere. Air stored Red Delicious did not maintain its textural eating quality well (in particular when statically cooled and subsequently stored at ambient temperatures) and to a lesser extent this was the case for Fuji (when stored ambient). Otherwise, sensory and instrumental quality of apples in the controlled study was mostly maintained well throughout the year. The exception was Red Delicious, at time point 4, in January which was somewhat floury.

Fruit sourced at point of sale from three supermarkets differing in apple turnover rate was also evaluated. Apples from a high turnover store were of the highest sensory quality, but some apples from the medium turn store were lower in eating quality than apples from the low turnover store. In some cases eating quality of apples at retail was poorer than apples in the controlled part of the study, which were kept at ambient temperatures for 10 days, suggesting factors other than storage temperature should be considered to explain losses in eating quality.

In general, consumer preferences for apples are determined by a combination of taste and texture characteristics. Consumer research fell outside the scope of this study and it is not known when fruit of lower eating quality becomes unacceptable to consumers, thereby influencing repeat purchase.