Custard apples Hoped to Break through Export Bottlenecks via Quick Freezing
Chen, Chia Wen（China Productivity Center agricultural Innovation Department）
Taiwan-produced custard apples (also called atemoya) are exported mainly in the form of fresh fruit. According to agricultural trade statistics, the China market accounted for over 90% of total custard apple exports in 2019 and 2020 each, with such large concentration reflecting large export risks. In addition, custard apples have not been exported to Japan because quarantine barriers there have not been overcome yet. As China temporarily laid a ban on imports of custard apples from Taiwan in 2021, exports of such fruit have dropped a great deal. Although the Taiwan government has actively helped custard apple producers tap other export markets than China, the increase in export is far insufficient to cover the loss in the China market.
Challenges to storage and transportation of custard apples
Because fresh custard apples are unable to withstand long-time storage during long-distance transportation, and conventional processing after they are picked is difficult to maintain stable good quality for shipping them to overseas markets far away from Taiwan. To solve the problem, Ministry of Agriculture (MOA) has helped custard apple producers and exporters apply for free licensed use of “technology of long-distance storage/transportation of custard apples” developed by National Taiwan University. In addition, MOA has encouraged them to adopt “custard apple ripening treatment and freezing technology” developed by Taitung District Agricultural Research and Extension Station, MOA in the hope of exporting quick-frozen custard apples to the Japan market and tapping other overseas markets.
Evaluation for Good-quality Custard Apples
China Productivity Center has been commissioned by MOA in 2023 to undertake the “Contest-based Evaluation for Good-quality Custard Apples” project, a bid to boost production of quick-frozen custard apples featuring safety, high quality and characteristic flavor specifically for tapping overseas markets. In the evaluation, quick-frozen custard apples are of two types of processing: “whole fruit group” and “dice/cut group”. All custard apples to be evaluated in the contest should be kept at below -18˚C in process of transportation and in standard package for export (packaged in Styrofoam boxes with sufficient dry ice and protective materials inside), with quick-frozen custard apples completely sealed (in vacuum without , dirt and thawing), as well as be attached with detailed product information.
Specifically considering food safety, quick-frozen custard apples in the contest should comply with “Sanitation Standard for Microorganisms in Foods” formulated by Ministry of Health and Welfare. In order to encourage safe use of pesticides and export promotion, all quick-frozen custard apples in the contest are tested and examined based on technical requirements specified in the “reference standards for application of pesticides and herbicides for exported custard apples” announced by Agricultural Chemicals Research Institute under MOA and the standard specifications for frozen food under Japan’s Food Sanitation Act.
Entirely based on blind tests for de-identification of producers/brands, the evaluation mainly consists of assessing outside appearance and tasting pulp of quick-frozen custard apples, with items and standards tabulated below:
| Group | Evaluation item | Sub-item |
Assessment weight |
Assessment criteria |
| Whole fruit | Appearance | Bruise damage | 10% | Assessment is based on extent of drug spots, physical damage (such as bruise), disease spots and insect spots. |
| Shape | 15% | Assessment is based on the shape, size, presence of exterior cracks and abnormal shapes of custard apples. | ||
| Color & luster | 15% | Green is normal color, and points are deducted depending on extent of browning. | ||
| Comment based on tasting | Appearance of pulp | 15% | Points are deducted depending on extent of water soaking and browning of pulp. | |
| Odor | 15% | It should have unique fruity aroma, and points are deducted depending on extent of odors of chemicals or those arising from deterioration. | ||
| Taste | 15% | Chewing to feel whether there is elastic texture with characteristic of fresh fruits | ||
| Flavor | 15% | Appropriate sweetness; points are deducted depending on extent of bitter or other unfavorable tastes. | ||
| Dice/cut | Appearance | Color & luster | 30% | Points are deducted depending on extent of water soaking and browning of pulp. |
| Comment based on tasting | Odor | 20% | It should have unique fruity aroma, and points are deducted depending on extent of odors of chemicals or those arising from deterioration. | |
| Taste | 30% | Chewing to feel whether there is elastic texture with characteristic of fresh fruits. | ||
| Flavor | 20% | Appropriate sweetness; points are deducted depending on extent of bitter or other unfavorable tastes. |
Conclusion
Along with increasing attractiveness for small-package, open-to-eat fruit products, promotion of the ripening technology of custard apples and whole-fruit quick freezing has made series quick-frozen custard apples available on some channels. These products include custard apple dices which are convenient to eat, whole custard apples to be thawed using microwave ovens and bar-shape custard apple ice cream, with all being characterized by tastes of sweetness and fine texture unique to custard apples. Custard apples, by virtue of the new style- quick-freezing processing, are hoped to break through quarantine bottlenecks in overseas markets to win international consumers’ favor.