Developmental differences in antioxidant compounds and systems in normal and small-phenotype fruit of ‘Hass’ avocado (Persea americana Mill.)

• ‘Hass’ avocado trees produced normal (NPF) and small-phenotype fruit (SPF).
• NPF were larger, weighed more and had greater protein concentrations than SPF.
• Developing NPF and SPF were larger on determinate than indeterminate floral shoots.
• SPF had greater antioxidant concentrations, capacity and enzyme activities than NPF.
• Antioxidant data suggest SPF would provide greater health benefits than NPF.

Antioxidant compounds and reactive oxygen-scavenging systems were investigated in ‘Hass’ avocado fruit set by determinate (DFS) and indeterminate floral shoots (IFS). During early development, DFS produced the largest fruit, IFS the smallest. Normal-phenotype (large) fruit (NPF) from DFS and IFS were faster growing, greater in length, diameter and weight and contained more protein than small-phenotype fruit (SPF) from DFS and IFS, resulting in SPF having greater ascorbic acid and total phenol concentrations and antioxidant capacity per g fresh weight. In contrast, NPF had greater catalase, ascorbate peroxidase, and glutathione reductase activities per g fresh weight than SPF on a greater number of sample dates; SPF had greater superoxide dismutase activity. Per mg protein, ascorbic acid and phenol concentrations, antioxidant capacity, peroxidase, polyphenol oxidase, catalase and ascorbate peroxidase activities were greater in SPF than NPF on more dates and at maturity. Thus, SPF would be a healthier food choice due to their greater antioxidant compounds and capacity compared to NPF.