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Does coconut oil help finger limes keep longer?
How cold should you keep freshly picked finger limes? In a University of Florida trial, fruit stored at 10 °C kept better than fruit stored at 5 °C, and a thin coat of coconut oil cut weight loss further.
Finger limes, the Australian native also known as lime caviar, are prone to chilling injury, which can shorten their storage life, reduce fruit quality and make them harder to sell. A team from UF/IFAS at the University of Florida wanted to know which storage temperature, which rootstock and which edible coatings keep the fruit in good condition for longest (Shahzad et al., 2026). The trees were grown in the open field in Florida, and the fruit was stored and tested in the university’s postharvest rooms.
What this means for your grow
If you grow finger limes, this trial suggests colder is not always better after picking: fruit held at 5 °C lost more weight and showed more peel disorders than fruit held at 10 °C. Brushing the fruit with plain coconut oil reduced weight loss compared with leaving it uncoated. The temperature results come from one cultivar and the coating results from two, all grown in Florida and stored in rooms at 90 to 95% relative humidity, so treat them as a guide, not a promise for your own fruit.
What did the team do?
The researchers ran two experiments over two seasons (2021 and 2022). In the first, they compared ‘DPI 50-36’, a white-pulp finger lime, grafted onto three rootstocks: Kuharske, Volkamer lemon and US-802. They checked the trees’ leaf nutrients and canopy size, then stored the ripe fruit at either 5 °C or 10 °C for 21 days, followed by 14 days at 20 °C to mimic shelf life.
In the second, they took ‘DPI 50-36’ and the red-pulp ‘UF SunLime’, both on Kuharske rootstock, and stored the fruit at 10 °C either uncoated, brushed with pure coconut oil, or brushed with a proprietary coating of water-soluble corn zein (a corn protein) plus coconut oil. Again, 21 days of cold storage were followed by 14 days at 20 °C.
Along the way they tracked weight loss, chilling injury (peel pitting), stem end rind breakdown, ageing, skin discolouration, decay, peel colour, juice total soluble solids (TSS) and acidity, and the share of fruit still fit to sell.
What did they find?
- 10 °C beat 5 °C. After the move to 20 °C, fruit that had been kept at 5 °C had 1.2-fold higher weight loss than fruit kept at 10 °C. Fruit from 5 °C also scored higher for chilling injury, ageing and peel discolouration.
- More fruit stayed sellable. All fruit kept at 10 °C maintained a higher percentage of marketable fruit (about 90%) than fruit stored at 5 °C.
- Coatings cut weight loss. Weight loss in uncoated fruit was 1.5-fold higher in ‘DPI 50-36’ and 1.3-fold higher in ‘UF SunLime’ than in fruit coated with coconut oil or the corn zein coating, at every time point.
- Coated fruit stayed more marketable. On days 28 and 35, in the 20 °C shelf-life period, coated fruit stayed more marketable than uncoated fruit, above 75% for ‘DPI 50-36’ and above 90% for ‘UF SunLime’.
- Rootstock mattered too. Trees on US-802 grew the largest canopy. Fruit on Kuharske and US-802 was heavier at harvest than fruit on Volkamer lemon. Fruit from Kuharske kept a higher proportion of marketable fruit (about 65%) than fruit from Volkamer lemon at all time points, and the authors rate Kuharske as the more suitable rootstock for finger lime growers in Florida.
What could it mean?
The authors recommend that finger limes can be stored at 10 °C for up to three weeks, plus one to two weeks of shelf life, while keeping fruit quality. They found that coconut oil or the corn zein coating, together with 10 °C storage, kept both white and red pulp types in good condition. They present this as practical guidance for handling and distributing Florida-grown finger limes, so it is aimed at commercial handling and distribution. If you grow your own, the storage temperature and a coconut oil coating are things you could try with your harvest.
What were the limitations?
- The authors say they cannot claim to have found the optimum storage temperature, which may lie somewhere between 5 °C and 10 °C.
- The trees were grown in Florida under conditions where Huanglongbing is endemic, and the authors frame the results for Florida growing conditions.
- Tree health (nutrients and canopy) was assessed in the 2022 season only.
- The authors say further research is needed to custom-design coatings for finger limes.
Trial details
- Where: United States. Trees grown under open-field conditions at the UF/IFAS Citrus Research and Education Center, Lake Alfred, Florida, under endemic Huanglongbing conditions. Fruit stored and tested at the Horticultural Sciences Department, University of Florida, Gainesville.
- Crop: finger lime (Citrus australasica). Five-year-old ‘DPI 50-36’ (white pulp) on Kuharske, Volkamer lemon and US-802 rootstocks; six-year-old ‘UF SunLime’ (red pulp) hybrid on Kuharske. Fully mature (ripe) ‘DPI 50-36’ fruit for the rootstock experiment harvested in November 2021 and December 2022.
- Growing: the rootstock-experiment trees all received the same fertilisation programme, following UF/IFAS recommendations for citrus in Florida.
- Storage: 5 °C or 10 °C at 90-95% relative humidity for 21 days, then 14 days at 20 °C and 90-95% relative humidity. Coated fruit: washed, brushed with a thin layer, dried at 23 °C and 45% relative humidity, then stored at 10 °C. In the rootstock experiment, fruit travelled to the postharvest facilities in a refrigerated van at 15 °C (about 2.5 hours).
- Treatments: rootstock (three) × storage temperature (two); and coating: uncoated control, pure coconut oil, or a proprietary water-soluble corn zein plus coconut oil coating from Akorn Technology (9.5% solids and 2% coconut oil).
- Design: 12 trees for tree health; 320 fully mature fruit collected and pooled from trees on each rootstock, with four replicates of ten fruit per treatment at each time point. Coating experiment: 240 fruit from ten trees per cultivar, four five-fruit replicates per treatment at each time point. Both experiments run in 2021 and 2022, with the two years’ means presented.
- Statistics: one-way and two-way ANOVA with Tukey’s HSD at p ≤ 0.05, in SigmaPlot 12.
- Results: weight loss 1.2-fold higher at 5 °C than 10 °C on days 28 and 35; about 90% marketable fruit at 10 °C; about 65% marketable fruit on Kuharske; weight loss of uncoated fruit 1.5-fold (‘DPI 50-36’) and 1.3-fold (‘UF SunLime’) higher than coated fruit; coated fruit above 75% (‘DPI 50-36’) and 90% (‘UF SunLime’) marketable on days 28 and 35.
- Funding: the authors state that financial support was not received for this work.
- Conflicts of interest: none declared.
- Publication: Frontiers in Horticulture, volume 5, published 29 October 2026, https://doi.org/10.3389/fhort.2026.2020470. Licence: CC BY 4.0.
- Not reported in the paper: irrigation, fertiliser rates, yield per tree, and the reasons for decay (the causal organism was not identified).
Links
- The study: Effects of rootstock, storage temperatures, and edible coatings on fruit quality and storage performance of finger lime (Citrus australasica)
- The research centre: UF/IFAS Citrus Research and Education Center
References
- Shahzad, F., Vashisth, T., Dutt, M., & Brecht, J. K. (2026). Effects of rootstock, storage temperatures, and edible coatings on fruit quality and storage performance of finger lime (Citrus australasica). Frontiers in Horticulture, 5. https://doi.org/10.3389/fhort.2026.2020470