Nutritional Value, Fourier Transform Infrared Spectroscopic Molecular Structures, Mycotoxines and Heavy Metals Concentration of Un-Ripe, Ripe and Sun-Dried Fruit from ‘Sultana’ Grapevine for Ruminants

Abstract

Grapes and grape-derived products have worldwide importance due to its consumption by human, however, they may also be used for ruminant feeding when their price or quality is low. The objectives of current study were to determine the nutritive value, in terms of chemical composition, <em>in vitro</em> rumen gas production kinetics and predicted nutrient supply, Fourier Transform Infrared Spectroscopic (FTIR) molecular structures and mycotoxin and heavy metal contaminants in un-ripe, ripe and sun-dried (raisin) fruits of ‘Sultana' grapevine for ruminants. Un-ripe fruit had higher nitrogen to total carbohydrate ratio and total phenol and tannin concentration (P<0.05) than ripe and sun-dried grapevine, and tended to have higher vibration spectroscopy peak area related to phenolic compounds and related to structural carbohydrates than ripe and sun dried fruit. Raisin had higher <em>in vitro</em> cumulative gas production at 24 h of incubation (P<0.05). Aflatoxin B1, B2, G1 and G2 and Ochratoxin A were not detectable in un-ripe and ripe grapevine fruit, while low concentrations were found in raisin (P<0.05). The lead concentration was lower in un-ripe fruit and raisin than in ripe fruit (P<0.05). In conclusion, phenolic compounds and tannins, mycotoxins and heavy metal concentration in un-ripe and ripe fruits and raisin of Sultana' grapevine were lower than toxic level for animal nutrition and nutrient profile and availability of the grapevine products make it a suitable feed to replace forage in the diet of ruminants.