Characterization of curd grain size and shape by 2-dimensional image analysis during the cheesemaking process in artisanal sheep dairies

Abstract

The size and shape of curd grains are the most important parameters used by cheesemakers to decide when to end the cutting or stirring processes during cheesemaking. Thus, 2-dimensional image analysis was used to measure the characteristics of curd grains in commercial cheese productions carried out by artisanal sheep dairies. Dairies used different technical settings for cutting and stirring steps, causing differences in the size and shape of curd grains. A linear relationship between total revolutions used for cutting and stirring and curd particle size was established. However, particle size distributions after curd cutting and stirring were highly heterogeneous. Actual cheese yield was correlated with particle size and cutting revolutions, whereas curd grain shape and fat loss were associated with stirring conditions by a multivariate approach. Image analysis of the size and shape of curd grains gives useful information for determining characteristics related to cheese yield and quality and may contribute to improving and controlling the cheesemaking process in small artisanal dairies.

Relationships between cheese-processing conditions and curd and cheese properties to improve the yield of Idiazabal cheese made in small artisan dairies: A multivariate approach

“…Then, curd grains and whey were separated and weighed in the laboratory for further analysis. For the image analysis of curd-grain features, FCG and SCG samples were obtained by submerging a mesh sieve halfway between the top and bottom of the vat right after the end of cutting and cooking, respectively (Aldalur et al, 2019a). Artisanal rennet paste (~50 g) was collected from each dairy, stored in plastic containers, and kept in refrigeration (4°C) until analysis.…”

“…Curd-grain size, shape, and particle size distribution (PSD) properties were measured by 2-dimensional image analysis using ImageJ software (National Institutes of Health, Bethesda, MD) as previously described by Aldalur et al (2019a). The values for area, perimeter, maximum Feret diameter, elongation, rectangularity, and circularity were measured for FCG and SCG.…”

“…Likewise, PSD traits were calculated based on the percentile dimensions of the area of the curd grains after cutting and cooking. The PSD traits described the degree of homogeneity of the curd particle sizes and the following indexes were used: uniformity index and coefficient, size range variation, relative span, and graphic skewness and kurtosis (Aldalur et al 2019a).…”

“…The cutting and cooking technical settings also affect the properties of the curd grains (Aldalur et al, 2019a), and thus their deformation capacity during pressing (Akkerman et al, 1996). It has been suggested that the deformation capacity of curd grains could have an important effect on the curd fusion during pressing, consequently affecting the texture of the cheese (Fagan et al, 2017).…”

“…It has been suggested that the deformation capacity of curd grains could have an important effect on the curd fusion during pressing, consequently affecting the texture of the cheese (Fagan et al, 2017). Moreover, the size distribution of curd particles has been reported to be heterogeneous in artisanal dairies (Iezzi et al, 2012;Aldalur et al, 2019a), and this could cause moisture distribution problems and defects in the cheese texture.…”