Scientists look to better flavour, mouthfeel from whey-based dairy
potential to enhance the thickness of whey-based lactic beverages.
"Results of this study indicated that high-methoxy pectin (HMP), [and] carboxymethyl cellulose (CMC) can be used to significantly increase the instrumental and perceived (sensory) viscosity of liquid whey to match the physical viscosity of lactic beverages," wrote lead author Francisco Gallardo-Escamilla in the International Dairy Journal.
According to market analyst Mintel, functional yoghurt drinks have been driving sales of yoghurt in the UK, with sales set to increase by 40 per cent over the next five years and smash the £2bn barrier by 2011.
Indeed, the sector is reported to have already grown by 432 per cent since 2001, and that 60 per cent of consumers cite health as the chief reason behind buying into the product.
"Whey-based lactic beverages constitute an emerging segment of non-conventional dairy products that require sensory, physical and chemical characterisation for quality control and product development," wrote the researchers from University College Cork, Ireland and the University of Otago, New Zealand.
The researchers looked at the effects of four hydrocolloids - high-methoxy pectin (HMP- 'Slendid' Type 200, CP Kelco); carboxymethyl cellulose (CMC - 'Ticalose CMC 2500 Std.', TIC Gums Inc.); propylene glycol alginate (PGA - 'Protanal GP 4650', FMC Biopolymers); and xanthan gum (XG - 'Keltrol', CP Kelco) on the mouthfeel and flavour of whey-based dairy drinks.
"To the best of our knowledge, there are no studies which have assessed the influence of adding hydrocolloids on the sensory properties of dairy beverages when unfractionated liquid whey is used as the sole milk protein source (i.e., with no caseins present) to produce fermented milk-type beverages," said Gallardo-Escamilla.
The researchers added the hydrocolloids to whey fermented by a yoghurt starter culture (YC-471, Chr. Hansen, Lactobacillus delbrueckii ssp. bulgaricus and Streptococcus thermophilus).
The results indicated that HMP, CMC and PGA all increased the thickness of the drink, but the PGA beverage had a 'gritty' characteristic that detracted from the mouthfeel of the yoghurt.
"Consequently, either CMC or HMP can be used to enhance the viscosity of whey-based lactic beverages, although both will tend to mask the typical flavour of yoghurt when using a yoghurt culture," said Gallardo-Escamilla.
However, the applicability of CMC is somewhat limited, said the researchers, because its use is recommended in a medium above pH 4.2, and phase separation may occur if the fermentation of the product takes place below this pH level.
Xanthan gum was not found to have any effect on the thickness, and did not interfere with flavour release.
"Results of this study support the assertion that the type of hydrocolloid, rather than its concentration, generally determines the observed effect on flavour intensity, mainly explained by chemical binding between the hydrocolloid and the aroma compounds," said Gallardo-Escamilla.
Source: International Dairy Journal On-line ahead of print. doi:10.1016/j.idairyj.2006.04.009 "Mouthfeel and flavour of fermented whey with added hydrocolloids" Authors: F.J. Gallardo-Escamilla, A.L. Kelly and C.M. Delahunty
