Pour savoir comment effectuer et gérer un dépôt de document, consultez le « Guide abrégé – Dépôt de documents » sur le site Web de la Bibliothèque. Pour toute question, écrivez à corpus@ulaval.ca.
 

Personne :
Turgeon, Sylvie

En cours de chargement...
Photo de profil

Adresse électronique

Date de naissance

Projets de recherche

Structures organisationnelles

Fonction

Nom de famille

Turgeon

Prénom

Sylvie

Affiliation

Université Laval. Département des sciences des aliments

ISNI

ORCID

Identifiant Canadiana

ncf10325454

person.page.name

Résultats de recherche

Voici les éléments 1 - 4 sur 4
En cours de chargement...
Vignette d'image
PublicationAccès libre

Relationship between smoothing temperature, storage time, syneresis and rheological properties of stirred yogurt

2020-05-23, Guénard Lampron, Valérie, Villeneuve, Sébastien, St-Gelais, Daniel, Turgeon, Sylvie

Six different smoothing temperatures were compared for nonfat yogurt and the changes in syneresis and rheological properties observed for up to 22 days. Multiple linear regressions were used to describe the syneresis, firmness, flow time, viscosity, and flow resistance and the relationship between these properties, the smoothing temperature and the storage time. During storage, viscosity, firmness, and flow time increased; syneresis and flow resistance remained stable. Syneresis increased significantly (P ≤ 0.05) with smoothing temperature (10–35 °C). Other properties increased slightly (P > 0.05), and properties started to decrease above 30 °C. Syneresis, viscosity, and flow resistance were more sensitive to smoothing temperature; firmness and flow time were more sensitive to storage time. Lower smoothing temperature (10 °C) should be used to minimize syneresis while smoothing temperature ranging from 25 to 30 °C is better to improve rheological properties. Storage time must be considered to optimize these properties.

En cours de chargement...
Vignette d'image
PublicationAccès libre

Studying stirred yogurt microstructure and its correlation to physical properties : a review

2021-06-19, Gilbert, Audrey, Turgeon, Sylvie

Microstructure is an important part of the understanding and the control of food properties as rheological properties, water holding and sensory properties. Stirred yogurt microstructure is being under study for decades. Observations at several length scales have been used to probe the structure. Some methods using optical techniques were recently introduced to provide a quick microstructure assessment of stirred yogurt. This review aims to provide a description of stirred yogurt microstructure and a short overview of the main techniques to characterize stirred yogurt microstructure allowing to highlight their complementarity. In general, stirred yogurt microstructure is described as a suspension of interconnected microgels into a continuous serum phase. While the relationship between yogurt microstructure and its physical and sensory properties has been discussed in numerous reviews, models or studies the impact of microgels sizes on rheological properties, water holding capacity, and creaminess, has not always been confirmed. Even if, other features such as microgels aggregation, shape, and compaction have shown to be involved in sensory or physical properties of stirred yogurt gel, a challenge remains for the characterization of microstructural characteristics of microgels without destructuring the network.

En cours de chargement...
Vignette d'image
PublicationAccès libre

Characterization of syneresis phenomena in stirred acid milk gel using low frequency nuclear magnetic resonance on hydrogen and image analyses

2020-04-15, Gilbert, Audrey, Rioux, Laurie-Eve, St-Gelais, Daniel, Turgeon, Sylvie

Water retention is an important quality attribute for yogurt. Classically, stirred yogurt water retention is investigated using induced syneresis measurement (centrifugation), which does not characterize spontaneous syneresis. Low-frequency nuclear magnetic resonance (1H-LF-NMR) is a non-destructive technique to detect spontaneous syneresis. Experimental yogurt from pasteurized skim milk, and commercial stirred yogurts were analyzed with 1H-LF-NMR. After Laplace's transformation of the signal, hydrogen atoms pools were differentiated according to their mobility. Each hydrogen pool stood for a type of water mobility in the matrices characterized by a relaxation time (T2(i)), and a signal intensity (I2(i)). Yogurt water retention was assessed by induced syneresis and their structure was characterized using microscopy. Low frequency 1H-NMR detected four different water mobility groups in the matrices. Among these, there was a signal from bulk water, and another attributed to the separated serum (spontaneous syneresis). In experimental yogurts, spontaneous syneresis was visible, resulting in induced syneresis higher than 50%. Moreover, induced syneresis and spontaneous syneresis detected by 1H-LF-NMR were similar. In commercial yogurts, bulk water mobility reduced with increasing protein content and protein network density. Induced syneresis and bulk-water mobility correlated only in yogurts without gelatin. In the presence of gelatin, the network was more open, probably favoring bulk water mobility. This study shows that 1H-LF-NMR associated with microscopy image analysis efficiently assesses and describes yogurts water retention and spontaneous syneresis.

En cours de chargement...
Vignette d'image
PublicationAccès libre

Impact of starch and exopolysaccharide-producing lactic acid bacteria on the properties of set and stirred yoghurts

2016-01-21, Gentès, Marie-Claude, Turgeon, Sylvie, St-Gelais, Daniel

The impact of exopolysaccharide (EPS)-producing lactic acid bacteria with well-known structures and starch (0.75%) on the rheological properties (apparent viscosity and elastic modulus) and physical properties (syneresis) of set and stirred yoghurts was studied. Three EPS-producing strains with different structural characteristics were studied: Streptococcus thermophilus ST1 (anionic, stiff and linear EPS), Lactobacillus delbrueckii subsp. bulgaricus LB1 (neutral, stiff and ramified EPS) and Lb. delbrueckii subsp. bulgaricus LB2 (neutral, flexible and highly ramified EPS). The presence of linear, stiff, and anionic EPS from ST1 increased the elastic modulus in all yoghurt conditions, possibly owing to electrostatic interactions with caseins. Higher viscosity values were obtained with stiff and linear or slightly branched EPS from the ST1 and LB1 for all yoghurt conditions. Starch addition increased the values of the rheological and physical properties of all stirred yoghurts, probably due to the repulsion between proteins and polysaccharides favouring thermodynamic incompatibility.