Assessment of fruit aroma for twenty-seven guava (Psidium guajava) accessions through three fruit developmental stages

摘要

Guava (Psidium guajava) fruit are valued for their rich, tropical aroma, but fruit quality data are lacking for many important cultivars. Guava is native to warm-climate areas of the Americas and is grown commercially in southern Florida, USA. Varieties relevant to south Florida display a high level of morphological diversity, including fruit color and shape. Fruit are commercially available at either a mature green stage which are harvested prior to full aroma development, or as mature yellow fruit which possess a full aroma profile. We sampled 27 guava accessions growing at the University of Florida's Tropical Research and Education Center for aroma at immature, mature green, and mature yellow fruit developmental stages. Variability in pulp pH (3-4.6) was not indicative of fruit maturity, but titratable acidity (0.17-3.6%) did decrease throughout fruit development. Aroma profiles showed significant differences among accessions. Some volatiles including hexanal, (E)-caryophyllene, and (E)-2-hexenal were common across guava accessions and were present at all developmental stages. Other compounds including (Z)-3-hexenyl acetate, ethyl butanoate, and ethyl octanoate had the greatest abundance only at the mature yellow stage of fruit development. Limonene, (E)-cadina-1,4-diene, and beta-ionone were abundant in some accessions and not detected in others (21, 10, and 14 out of 27 accessions, respectively). This work describes the comparative diversity of guava fruit quality for a large number of accessions through fruit development for the first time. Furthermore, these fruit quality data could support future breeding work towards the genetic improvement of guava flavor.