Fruit Quality Changes of Salak “Pondoh” Fruits (Salacca zalacca (Gaertn.) Voss) during Maturation and Ripening

Salak is a very important fruit product in Indonesia that has been cultivated throughout Indonesia and has been exported to several countries. The study to determine biochemical and physical as well as physiological changes during fruit maturation and ripening was applied to two superior salak cultivars, “pondoh hitam” and “pondoh super” originally from Sleman, Yogyakarta of Indonesia. Fresh salak fruits of the cultivars “pondoh hitam” and “pondoh super” at three different ripening stages were used, i.e. stage 4, stage 5 and stage 5.5 (4, 5 and 5.5 months after pollination, respectively) for “pondoh hitam” and stage 4, stage 5 and stage 6 (4, 5 and 6 months after pollination, respectively) for “pondoh super”. Immediately after air transport from Indonesia to Germany, determination of fruit colour and texture as well as biochemical analyses were carried out in Berlin. Freeze-dried sample material was used for the determination of minerals, mono- and disaccharides, pectic substances and dietary fibre. Results of the study showed that increase in fruit size and weight as well as changes in peel and pulp colour occurred during maturation and ripening of salak fruits. Different patterns of peel and pulp colour changes were found in “pondoh super” and “pondoh hitam” during ripening. Physiological processes in “pondoh super” occurred to at a later stage but then accelerated faster than “pondoh hitam” in term of changes of mono- and disaccharides, resulting in a poorer marketability and shorter shelf life. In respect to the changes of sugar/acid ratio, there was a faster ripening process in “pondoh super” than in “pondoh hitam”. “Pondoh super” possessed higher content of polysaccharides and lignin, however, the ripening process accelerated earlier in comparison to “pondoh hitam”. Alterations in cell wall and middle lamella structure did not correlated with the physical non destructive texture measurement during ripening of salak.