Development of a Novel Robust Approach for Unveiling the Stretchiness of Cheese

Abstract

This study proposed a method for objectively measuring the stretchiness of cheese using a texture analyzer equipped with a double-sided fork probe. The method measures the force required to stretch melted cheese samples at a constant speed. Using a central composite design (CCD) experimental approach, the impact of test parameters (i.e., sample quantity, temperature, speed) has been evaluated. Subsequently, an optimal combination of the test parameters (i.e., 66°C, 17.5 mm/s, 6.7 g sample) has been proposed. These aimed to minimize variability and ensure the reproducibility of the results in the stretchiness of the observed cheese. The key stretch descriptors' significance to describe the stretchiness of cheese, namely peak force, force and work at a distance of 40 mm, and breaking distance has also been indicated. With the proposed method, changes in the stretch properties of Mozzarella during storage at 4°C were able to be monitored. An initial decrease was observed up to day 7, followed by a slight increase by day 25, suggesting changes in the cheese protein network. The method was then used to compare the properties of 15 dairy-based cheeses and 6 vegan Mozzarella-style cheese alternatives. The peak force and filament strength (i.e., force at a distance of 40 mm) were used to cluster various cheeses showing distinct stretch profiles. Mozzarella cheeses generally showed lower resistance to filament formation compared to other dairy-based cheeses, while vegan cheeses exhibited minimal to no filament formation and lower meltability. By comparing and clustering the stretchiness properties of dairy cheeses and their vegan alternatives, the present method can be used to guide researchers and product developers on better profiling the stretch properties of target cheese and subsequently producing (new) products with a more desirable stretch profile.

Keywords: cheese; meltability; mozzarella; stretchability; texture analyzer.

FIGURE 1

A typical stress–strain curve resulting from the tensile test of some plastic polymers.

FIGURE 2

Comparison of cheese extensibility probes. (A) Top view of the Stable Micro Systems cheese extensibility rig (above) and the scaled‐down 3D printed probe used in this study (below). (B) Texture analyzer equipped with the scaled‐down probe during a stretch test of mozzarella sample. (C) Similar setup as in (B), but with the Stable Micro Systems cheese extensibility rig. (D) Detailed view of a slippage problem encountered with some of the Mozzarella samples using the cheese extensibility rig, with red arrows indicating the visible arc in the sample caused by the slippage.

FIGURE 3

Typical stretch profile of melted cheese and the key stretch descriptors (i.e., peak force, filament strength at a 40 mm stretch, work done during stretching, and breaking distance).

FIGURE 4

Pareto charts of standardized effects for responses of filament strength and peak force. Standardized effects for filament strength response (A) and peak force response (B). The vertical lines in the charts (i.e., at the value of 2.01) represent the threshold of significance at an alpha level of 0.05, highlighting factors that significantly influence the responses.

FIGURE 5

Surface plots for peak force and filament strength responses. Surface plots show the effects of sample quantity, test speed, and test temperature on peak force (A) and filament strength (B), with one factor fixed in each plot (sample quantity = 6.7 g; test temperature = 66°C; test speed = 17.5 mm/s).

FIGURE 6

Peak force (N) and filament strength (N) measured during 25 days of storage for a Mozzarella “Galbani Cucina”. Vertical bars represent the standard deviation (s.d.) of the measurements (n = 5).

FIGURE 7

Stretch parameters of 21 different cheeses, as described by peak force and filament strength. Each point on the plot corresponds to one cheese sample, with different colors representing different cheese categories: Gouda, Mozzarella, Vegan, Provola, and Cheddar. Error bars represent the standard deviation (s.d.) for both peak force and filament strength (n = 5).