Page 54 - FoodFocusThailand No.205 April 2023

STRONG QC & QA

Table 1 The sources of NIAS in various types of food contact materials
Method Analyzed properties Application
Mechanics
Shearing test - Maximal shearing force Comparison of meat analogs and real meat pre-pared in sous-vide
- Texture index
Puncture Penetration force Effect of binding agents on sausage analog quality
Texture Profile Texture index (springiness, cohesiveness, gumminess, hardness, Examinations of the extrusion parameter influence
chewiness)
Structure
Microscopy (Light, Microstructure and anisotropy Examinations of extrusion parameter influence and blend ratios in
scanning electron, laser feed
scanning)
X-ray microtomography Structure porosity (air in-corporation) Blend comparisons
Fourier infrared Protein secondary structure Influences of processing parameters and feed
spectroscopy

describe the fiber formation to confirm the similarity with the and processed in fibrous formation according to equation
original product. Although a high-resolution camera can capture (1). The fluorescence polarization indicates the structural
the structure, it has limitations in the sample preparation step, change in meat analog. If the sample has a high polarization
and visual examination does not provide an accurate numeric value, it indicates that the sample has changed its structure
index comparison between products. from being a batter to a more fibrous sample as it emerges
Most plant-based meats contain soy protein, pea protein, from the die, which shows good fiber alignment.
wheat gluten, and modified starch in an appropriate ratio and
are formed in a twin screw extruder under high moisture
conditions in the range of 60-72%. Under this condition, this
plant protein can form a fibrous structure similar to chicken
breast meat. It is because the operation of the extruder utilizes
a combination of kneading, mixing, shearing, heating, and P is the degree of polarization
forming. The raw material in the barrel receives mechanical I is the fluorescence intensity measured when the
o
force from the friction of the rotating screw inside and heat polarizer (P ) is at 0° with the polarizer (P )
energy can change the raw material into dough and cook it into I is the fluorescence intensity measured when the
2
1
90
a gel. The proteins were denatured, unfolded, and rearranged polarizer (P ) is at 90° with the polarizer (P )
1
during the movement to the die, resulting in a fibrous structure The fluorescence spectroscopy method can identify the
2
and promoting a better appearance and taste of the product. difference between fibrous and normal structures. Therefore,
The degree of fiber formation in the meat analog was analyzed it can be used as a guideline to create meat analogs from
by using illumination from a light source (LED) at a wavelength plant proteins that are close to the original product and
of 375 nm. The excitation light was collimated by a lens and convince consumers to accept plant-based food.
polarized by a polarizer. This light will stimulate the molecules
within a sample to cause absorption, and it emits fluorescent
light at a wavelength of 540 nm. The fluorescence light from
the sample passed through another polarizer, was collected
by a fiber probe, and detected by a spectrometer as follows in
figure 1.

Figure 1 Fluorescence polarization measurements Figure 2 The typical raw fluorescence spectrum from extruded products

A typical spectrum is shown in Figure 2. The peak at 375
nm is from the excitation light. The fluorescence emission is
rather broadband at 540 nm. The signal intensity when More Information Service Info C009
molecules released energy to the ground state was recorded

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