Nutritional and physicochemical evaluations of tahina (sesame butter) prepared from heat‐treated sesame seeds

Abstract

Dehulled sesame seeds were roasted using different heat treatments. The effects of roasting treatments on the nutritive value, physicochemical properties and sensory properties of produced tahina were studied. Resultant tahina contained 586–594 g kg−1 crude oil, 219–226 g kg−1 crude protein and <30 g kg−1 crude fibre and ash. Crude protein, crude fibre, ash and N-free extract in tahina samples were not affected by roasting treatments. However, crude oil was decreased by steam roasting and hot plate roasting. Hot plate roasting was more effective in reducing raffinose content than other roasting treatments, whereas vacuum roasting was less effective in reducing raffinose content than other roasting treatments. Tahinas were good sources of essential amino acids, especially sulphur-containing amino acids, aromatic amino acids and tryptophan. Hot air roasted tahina followed by vacuum roasted tahina had higher total essential amino acid contents than steam roasted and hot plate roasted tahinas. Lysine was the first limiting amino acid in tahinas. Tahinas had a relatively high in vitro protein digestibility (over 83%). Tahina is a good source of niacin. Hot air roasted tahina had the highest content of B group vitamins compared with other tahina samples. Resultant tahinas had relatively high amounts of Na, Mg, K, Cu, Zn and Fe and a low amount of Ca. Roasting treatments did not affect the mineral contents. All roasted samples had a typical protein spectrum with a maximum absorption at 280 nm and minimum at 260 nm. However, the spectrum of hot air roasted tahina proteins was sharper than the spectra of other tahina proteins. Size exclusion HPLC fractionated tahina proteins into two fractions for hot roasted and vacuum roasted tahinas and three fractions for steam roasted and hot plate roasted tahinas. The gel filtration pattern of tahina proteins contained four peaks with identical elution volumes but different proportions. Hot air roasted and vacuum roasted tahinas had higher panel scores than steam roasted and hot plate roasted tahinas for all tested sensory properties. © 2000 Society of Chemical Industry