Cold storage potential of three underutilized native fruit species from South Mozambique: promoting exploitation for nutrition and business

Abstract

The exploitation of underutilized indigenous species from agroforestry systems improves the resilience of smallholders' agricultural systems. In Mozambique, consumption of native fruits is a strategy used by rural populations to obtain food during seasonal periods of critical hunger. The inclusion of fruits in the diets has the additional advantage of providing nutrients and antioxidants, fighting malnutrition and “hidden hunger”. Exploitation of native fruits towards introduction of added value can also leverage the creation of new businesses and the development of new value-chains. Native fruits are collected and consumed fresh and, during surplus periods, are sold in local markets to obtain revenues to buy other foods and basic goods. Native fruits are usually not stored for later consumption or trade and no knowledge exists on their specific physiology and related storage aptitude. In this work, the cold storage potential was evaluated in three priority species: Uapaca kirkiana, Strychnos spinosa and S. madagascariensis. Under four temperature regimes, -20, 5, 12°C and room temperature, the physical-chemical and quality evolution was followed along 120-d storage. The results disclosed that under >0°C cold storage temperatures, U. kirkiana had the lowest conservation capacity, since after 30 d at 5°C, all fruits were rotten or chilled injured and at 12°C the pulps were totally desiccated. After 60 d cold storage at 12°C, Strychnos sp. presented ca. 2/3 or 2/5 acceptable fruits, respectively, for S. spinosa and S. madagascariensis, disclosing distinct potential for cold preservation. At -20°C, fruits from all species could be stored for 120 d, although with external symptoms of injury by browning. Nonetheless, pulps were significantly less or not affected, particularly in Strychnos. Under freezing, in this genus, at 120 d storage, decreased TSS and increased acidity were recorded for S. spinosa, while for S. madagascariensis both TSS and pH were lowered.