Qualitative traits of different varieties of guar grown in Southern Italy

Inadequate availability and increasing prices of quality feed
ingredients have made it increasingly difficult to formulate a balanced
and least cost animal feed. This situation advocates the
exploration of non-conventional feed resource. Guar (Cyamopsis
tetragonoloba L.) is an interesting summer legume crop used in
many industrial activity, which by-product named guar meal,
have a well-recognised application as animal feeding due to its
high protein content. The aim of the present research was to
assess the qualitative traits of eight varieties of guar with different
origin: India, South Africa and USA (Kinman, Lewis Matador
and Monument) grown in Southern Italy. The trial was carried
out in 2012 in Gela Plain on a clay soil adopting a randomised
block design with three replications. Seeds were analysed for the
main qualitative traits (protein, oil, fibre, ash) and polyphenols.
The amount of total phenols was measured by using a UV-VIS
spectrophotometer (UV-2600 Shimadzu), at the absorbance of
760 nm. Gallic acid was used as a positive control. Total phenol
values were expressed in terms of gallic acid equivalent-GAE
(mg/g of extracted compounds). All data were submitted to oneway
ANOVA (percentage data were previously arcsine transformed)
and Tukey’s HSD was adopted as multiple comparison
test. The mean values of dry matter for the eight varieties of guar
was of 89.8%, on average. Protein content (g 100 g-1 as fed) of the
whole seed ranged between 21.2 of Matador and 32.1 of India 2,
with an average value of 26.8 and a CV of 17.8. Oil content (g 100
g-1 as fed), as reported in literature was quite low, with only
South Africa variety that overpassed 3.0. Crude fibre (g 100 g-1 as
fed) was on average 10.3 showing the lowest variability (4.2).
Ash content (g 100 g-1 as fed) ranged between 5.32 of Matador
and 3.62 of India 2, following the trend already seen for protein
content. Polyphenol content (mg g-1 of GAE) was very high in
Kinman (6.63) and very low in Indian varieties (1.61, on average
for the three varieties) with a very high variability (52.2).
Results of qualitative parameters indicate guar as a possible
cheap and valuable feed source.