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.