Sugar Content and Physical Characterization of Four Selected African Nightshade (Solanum nigrum) Edible Berries

Fruits constitute a major part of the diet in many parts of the world, highly recommended for the nutritional value derived from them. Fruit maturity is an important determinant of the quality as it affects the appearance, an aspect of quality considered by most consumers. Sugar content, colour, size and firmness are some of the quality indicators associated with maturity. While the ripening and maturity indicators are well documented for climacteric fruits, non-climacteric fruits such as berries lag behind. African nightshade (Solanum nigrum L.) edible berries are among them. This study evaluated the quality parameters of the edible berries of four varieties of African nightshade and found out that they accumulate glucose and fructose as they ripen with glucose being the most abundant sugar. Sucrose is only present during the senescence stage. Size remained relatively constant within each variety while firmness decreased progressively after veraison. Black NS differed with the others in colour besides fructose and sucrose content at 29.35 and 388.40 mg/100g, respectively. Giant NS recorded the highest glucose content at 172.44 mg/100g when ripe. Conclusively, the African nightshade berries are characteristically similar to other non-climacteric fruits adopted as part of the normal diet and should be considered as a valuable addition to the diet.