Effect of dairy powders fortification on yogurt textural and sensorial properties: a review

Abstract

Yogurts are important dairy products that have known a rapid market growth over the past few decades. Industrial yogurt manufacture involves different processing steps. Among them, protein fortification of the milk base is elemental. It greatly enhances yogurt nutritional and functional properties and prevents syneresis, an undesirable yogurt textural defect. Protein enrichment can be achieved by either concentration process (evaporation under vacuum and membrane processing: reverse osmosis and/or ultrafiltration) or by addition of dairy ingredients. Traditionally, skim milk powder (SMP) is used to enrich the milk base before fermentation. However, increased quality and availability of other dairy ingredients such as milk protein isolates (MPI), milk protein concentrates (MPC) whey protein isolates (WPI) and concentrates (WPC), micellar casein (MC) and caseinates have promoted their use as alternatives to SMP. Substituting different dry ingredients for skim milk powder in yogurt making affects the yogurt mix protein composition and subsequent textural and sensorial properties. This review focuses on various type of milk protein used for fortification purposes and their influence on these properties.

Role of Whey Protein-Casein Complexes on Yoghurt Texture

“…As the milk pH 6.7 is reduced by the action of starter culture and reached to the isoelectric point of casein (pH 4.6), the net negative charge of casein decreases leading to collapsed of hairy layer of -casein (De Brabandere and De Baerdemaeker, 1999;. Consequently it decreases in electrostatic repulsions as well as steric stabilization and increases in casein-casein interactions prompt the formation of a three dimensional protein networks (Lee and Lucey, 2010;Karam et al, 2013;Meletharayil et al, 2015), as presented in Fig.1.…”

“…Consequently, thiol disulphide interchange reactions occur during acidification of heated milk and form covalent bonds that contribute to the strength of yoghurt gel (Matumoto-Pintro et al, 2011). Earlier studies had described widely the heat induceddenaturation and interaction of whey proteins in the skim milk with or without added whey protein (Lucey et al, 1999;Karam et al, 2013). Heat induced-denatured whey protein are partly associated with casein micelles as micelle-bound complexes occur at low milk pH by forming disulphide bond with -casein at the surface of the micelles and partly in serum phase as soluble whey protein/ -casein complex occur at high milk pH, because of more -casein dissociates from casein micelles at these conditions (Anema and Li, 2003;Guyomarc h et al, 2003a;Xu et al, 2015).…”

“…Yoghurt is a very popular fermented milk product produced all over the world (Lucey and Singh, 1998;Karam et al, 2013), in which starter cultures are used to reduce milk pH resulting to form yoghurt gel (Peng et al, 2009). During fermentation, casein becomes unstable and coagulates after reaching the isoelectric point of the casein (pH 4.6), and the casein formed a three dimensional protein networks in which whey is entrapped (Damin et al, 2009).…”

Impacts of pH-mediated EPS structure on probiotic bacterial pili–whey proteins interactions

“…The hypothesis of the present study is that bacterial surface structure are affected when decreasing the pH which could affect interactions between bacteria and dairy proteins. For practical reasons, two pH values were selected in this work: 6 [11] reached after milk acidification in the absence of protein coagulation [8]. The dependence of LGG-whey proteins interactions on pH is addressed via the measurement of adhesion forces between LGG bacteria strains lacking or not pili and/or exopolysaccharides (EPS) at their surface and protein-coated AFM colloidal probes.…”

Functionalization of yogurts with Agaricus bisporus extracts encapsulated in spray-dried maltodextrin crosslinked with citric acid

“…Yogurt is among the most studied products, most likely because it is a cheap product, generally appreciated by most consumers, besides having intrinsic beneficial properties (Pereira et al, 2016;Pereira et al, 2016). Nevertheless, due to their high water content yogurts are mainly appropriate to be functionalized with hydrophilic extracts (Caleja et al, 2016;Ghorbanzade, Jafari, Akhavan, & Hadavi, 2017;Karaaslan, Ozden, Vardin, & Turkoglu, 2011;Karam, Gaiani, Hosri, Burgain, & Scher, 2013;Santillán-Urquiza, Méndez-Rojas, & Vélez-Ruiz, 2017;Singh & Muthukumarappan, 2008).…”