3. Results and discussion
Proximate composition of kiwifruit grown in the five selected
orchards is reported in Table 1. Kiwifruit showed a high water
content (mean value 84.4 g/100 g), a common characteristic of
fresh fruit and, consequently a low content in macronutrients;
among these, protein (0.9 g/100 g) and lipid (0.1 g/100 g) were
detected in very low amounts, but on the other hand carbohydrates
were the most represented showing a mean value of 9.0 g/100 g.
Among kiwifruit orchards, those grown in Borgo Podgora showed
the lowest moisture and protein amount and the highest
carbohydrate amounts. Fructose was the monosaccharide found
in the highest amount among the orchards (mean value 4.5 g/
100 g), followed by glucose (mean value 4.0 g/100 g) and sucrose
(mean value 1.34 g/100 g). The differences in simple sugars
observed among orchards were mainly dependent on the ripening
stage of the fruit, which induced a progressive starch degradation.
Starch was almost completely degraded in the ripe fruit. The total
dietary fiber content was on average 2.5 g/100 g (ranging from
2.3 to 2.83 g/100 g); this provides about 10% of the Italian
suggested daily requirement for dietary fiber (LARN, 1996). The
total dietary fiber content found in this study was similar to that
previously reported for the same cultivar (Lombardi-Boccia et al.,
1986). A variation in total oxalic acid content among orchards was
observed, ranging from 6.0 to 10.0 mg/100 g (mean value 8.0 mg/
100 g); most of the oxalic acid was in the insoluble form (mean
value 6.0 mg/100 g). No differences in organic acids content
among orchards were detected: citric acid content was on
average 1.2 mg/100 g, malic acid was detected in very low
amount (mean value 0.24 mg/100 g).