Rapid Differentiation of Unfrozen and Frozen-Thawed Tuna with Non-Destructive Methods and Classification Models: Bioelectrical Impedance Analysis (BIA), Near-Infrared Spectroscopy (NIR) and Time Domain Reflectometry (TDR)

The performances of three non-destructive sensors, based on different principles, bioelectrical impedance analysis (BIA), near-infrared spectroscopy (NIR) and time domain reflectometry (TDR), were studied to discriminate between unfrozen and frozen-thawed fish. Bigeye tuna (Thunnus obesus) was selected as a model to evaluate these technologies. The addition of water and additives is usual in the fish industry, thus, in order to have a wide range of possible commercial conditions, some samples were injected with different water solutions (based on different concentrations of salt, polyphosphates and a protein hydrolysate solution). Three different models, based on partial least squares discriminant analysis (PLS-DA), were developed for each technology. This is a linear classification method that combines the properties of partial least squares (PLS) regression with the classification power of a discriminant technique. The results obtained in the evaluation of the test set were satisfactory for all the sensors, giving NIR the best performance (accuracy = 0.91, error rate = 0.10). Nevertheless, the classification accomplished with BIA and TDR data resulted also satisfactory and almost equally as good, with accuracies of 0.88 and 0.86 and error rates of 0.14 and 0.15, respectively. This work opens new possibilities to discriminate between unfrozen and frozen-thawed fish samples with different non-destructive alternatives, regardless of whether or not they have added water.

THE RELATIONSHIP BETWEEN BODY MASS INDEX AND BODY FAT PERCENTAGE, ESTIMATED BY BIOELECTRICAL IMPEDANCE IN A GROUP OF ROMANIAN FEMALE STUDENTS

Bioelectrical impedance analysis (BIA) also called bioelectrical impedance (BEI) is a non-invasive method based on the electric conductibility properties of tissues and is a commonly used technique for estimating body composition.Percentage of body fat is strongly associated with the risk of several chronic diseases but its accurate measurement is difficult. Body Mass Index is a useful population-level measure of overweight and obesity. It is used for all categories of people, male or female.The main objective of this study was to determine if there is a relationship between BMI and body fat percentage (BF%) in a group of Romanian female students. This relationship has been studiedin various ethnic groups before. To conduct the study, we examined 29 young females (aged 20-36 years old) estimating BF% from bioelectrical impedance analysis using Tanita Body Fat Monitor Scale UM-076.In this research group, the BMI and BodyFat dependent variables have a moderate to strong correlation (r = .839; 0.75 < r < 1), the favorable score for the first measurement being a statistically relevant benchmark for the second (sig < 0.05).

FEATURES OF NUTRITIONAL STATUS IN CHILDREN WITH SPASTIC CEREBRAL PALSY

Children with spastic cerebral palsy (CP) are at risk of undernutrition, which increases with the severity of movement disorders. Objective of the study: to assess and compare anthropometric indicators and body composition in children with cerebral palsy, depending on the level of impairment of gross motor function classification system (GMFCS). Materials and methods of research: 102 children were included in a prospective open-label comparative single-center non-randomized study: 58 (56.8%) boys and 44 (43.1%) girls with cerebral palsy aged 2 years to 16 years and 9 months who were undergoing rehabilitation in the National Medical Research Center of Children's Health in the period from 2019 to 2021. Anthropometric measurements (body weight, length, knee height, triceps and subscapular skinfold thicknesses) were performed on admission. Body fat percentage (%FM) was calculated by CP-modified (Gurka) equations and compared with results obtained using bioelectrical impedance analysis. A survey on the EDACS scale was performed to determine the ability to eat and drink. Results: patients were divided into 2 groups: the main group – 53 children (52%) with GMFCS levels IV–V and a comparison group – 49 children (48%) with GMFCS levels I–III. The groups did not differ statistically significantly in terms of gender (p=0.956) and age (p=0.207). The median age in the main group was 7.1 years, in the comparison group – 5.3 years. Children of the main group had statistically significantly lower growth indicators (HAZ1 –1.5 [–2.6; –0.74] and HAZ2 –0.58 [–1.59; 0.44], p=0.003), BMI (BAZ1 –2.43 [–3.67; –0.93]; BAZ2 –0.91 [–1.942; 0.28], p<0.001), higher frequency of oromotor dysfunction (42% and 4%, p< 0.001), the percentage of severe wasting (59% and 16%, p<0.001; OR 7.2 (95% CI 2.8–18.4) (p<0.001). There was no significant difference in %FM between children of main and comparison groups. Patients even with moderate and severe undernutrition according to WHO criteria had normal or excess %FM. A moderate positive correlation was found between %FM calculated using the Gurka equations and those obtained by bioelectrical impedance analysis (r=0.565, p=0.002). Conclusions: anthropometric indicators in children with CP deteriorate with an increase in the degree of neurological deficit. The use of BMI as the only marker of nutritional status is insufficient to properly diagnose of undernutrition and identify patients needed in nutritional interventions. For an adequate analysis of the nutritional status of children with CP, it is necessary to assess the body composition (measurement of the skinfold thicknesses or bioelectrical impedance analysis).

Application of Accu-Chek® Test Strips as inexpensive microelectrodes for BIA research

In the midst of an investigation to perform bioelectrical impedance analysis (BIA), we were faced with the need to search for optimally adjusted electrodes to perform reading in small biological samples. The best option to carry out these readings is the well-known gold microelectrodes; however, these are very expensive for our research purposes. For this reason, we found an alternative using Accu-Chek Performa test strips as reading microelectrodes due to their low cost and ease of disposal. This article contains an in-depth detail of the components of the Accu-Chek Performa test strip and the process that was used so that they could be suitable for taking measurements on biological material. In addition, a measurement scheme is shown in conclusion to the operation of the test strip as a microelectrode and the possible problems to consider if it is to be used for future research.