Jasenka Gajdoš Kljusurić

Stability of polyphenols in chokeberry juice treated with gas phase plasma

Chokeberry juice was subjected to cold atmospheric gas phase plasma and changes in hydroxycinnamic acids, flavonols and anthocyanins were monitored. Plasma treatments were carried out under different treatment times and juice volumes under constant gas flow (0.75dm(3)min(-1)). The results were compared against control (untreated) and pasteurized chokeberry juice (80°C/2min). During pasteurization, the most unstable were hydroxycinnamic acids with losses of up to 59%, while flavonols and anthocyanins increased by 5% and 9%, respectively. On the contrary, plasma treated chokeberry juice showed higher concentrations of hydroxycinnamic acids and 23% loss of anthocyanins in comparison to untreated juice. In order to obtain the optimal cold plasma treatment parameters principal component and sensitivity analysis were used. Such parameters can be potentially used for pasteurization in terms of phenolic stability of chokeberry juice. Optimal treatment was at 4.1min and sample volume of 3cm(3).

Gas phase plasma impact on phenolic compounds in pomegranate juice

The aim of the study was to evaluate the effect of gas phase plasma on phenolic compounds in pomegranate juice. The potential of near infrared reflectance spectroscopy combined with partial least squares for monitoring the stability of phenolic compounds during plasma treatment was explored, too. Experiments are designed to investigate the effect of plasma operating conditions (treatment time 3, 5, 7 min; sample volume 3, 4, 5 cm(3); gas flow 0.75, 1, 1.25 dm(3) min(-1)) on phenolic compounds and compared to pasteurized and untreated pomegranate juice. Pasteurization and plasma treatment resulted in total phenolic content increasing by 29.55% and 33.03%, respectively. Principal component analysis and sensitivity analysis outputted the optimal treatment design with plasma that could match the pasteurized sample concerning the phenolic stability (5 min/4 cm(3)/0.75 dm(3) min(-1)). Obtained results demonstrate the potential of near infrared reflectance spectroscopy that can be successfully used to evaluate the quality of pomegranate juice upon plasma treatment considering the phenolic compounds.

Determination of histamine in fish by Surface Enhanced Raman Spectroscopy using silver colloid SERS substrates

This study was focused on development of a rapid and sensitive method for histamine determination in fish based on Surface Enhanced Raman Spectroscopy (SERS) using simple and widely available silver colloid SERS substrate. Extraction of histamine with 0.4M perchloric acid and purification with 1-butanol significantly shortened sample preparation (30min) and provided clear SERS spectra with characteristic Raman bands of histamine. Principal component analysis effectively distinguished SERS spectra of fish samples with different histamine content. Partial least square (PLS) regression models confirmed reliability of detection and spectral analysis of histamine with SERS. In histamine concentration range 0-200mgkg-1, significant in legislative and fish quality control aspects, PLS regression model based on spectral range 1139.9-1643.7cm-1 showed linear trend with R2pred=0.962, RPD=7.250. Presented protocol for histamine extraction and purification followed by SERS analysis coupled with chemometric approach, enabled development of rapid and inexpensive method for histamine determination in fish.

Wine with geographical indication – awareness of Croatian consumers

Purpose – Quality and top quality wines (wines with geographical indication (GI)) have a larger share (59 per cent) on the Croatian market and this was one of the reasons for defining the subject of the research. Although there are a few market research studies, none of them is completely oriented on the role and market significance of GI of wine. There is an evident lack of information in this field. This paper aims to address these issues.Design/methodology/approach – The population of the basic group is a high‐qualified population for reviewing different aspects of wine as a complex product. Stratification of the units from the sample has been made on the sample (n=200). Data were analysed using univariate statistics, bivariate correlations and multiple factor analysis.Findings – Results have shown a high correlation degree between the higher socioeconomic status of examinees and preferences for wine with GI. It might be concluded that examinees with a higher level of education are more familiar with w...

Differences in daily nutritive value of meals and daily intake among schoolchildren accommodated in boarding schools

This paper describes a meal analysis that included 17 Croatian boarding schools and 668 girls and 592 boys, aged 14–18, accommodated in them that participated in the questionnaire. The aim is to compare the differences among different boarding schools in one year and to compare the changes according to the years from 1997 to 2001. During the survey several consumption frequencies were found to be low, such as intake of milk, vegetables and fruits if they are not included in the meal offered by the boarding school. The self-administrated food frequency questionnaire correctly describes food consumption in boarding school-accommodated schoolchildren. Moreover, it was well accepted by the target group, and easily understood. The results show that a significant proportion of schoolchildren did not consume enough milk, fruit and vegetables on a daily basis or did not consume it at all.This paper describes a meal analysis that included 17 Croatian boarding schools and 668 girls and 592 boys, aged 14-18, accommodated in them that participated in the questionnaire. The aim is to compare the differences among different boarding schools in one year and to compare the changes according to the years from 1997 to 2001. During the survey several consumption frequencies were found to be low, such as intake of milk, vegetables and fruits if they are not included in the meal offered by the boarding school. The self-administrated food frequency questionnaire correctly describes food consumption in boarding school-accommodated schoolchildren. Moreover, it was well accepted by the target group, and easily understood. The results show that a significant proportion of schoolchildren did not consume enough milk, fruit and vegetables on a daily basis or did not consume it at all.

Geographical region as a factor influencing consumers’ perception of functional food – case of Croatia

Purpose – In recent years, consumers have developed an interest in the type and the quality of food they eat. As consumers’ opinion is very important in identifying development strategy for food industry it seems justified finding out if geographical region had an influence on consumers’ opinion. Furthermore, this is the topic that is still under researched. The purpose of this paper is to investigate consumers’ perception of functional food (FF) relative to geographical region. Design/methodology/approach – Questionnaire based survey was conducted on a representative national sample with participants aged 18 and older (n=687). Participants were divided according to their place of residence taking into account difference in dietary habits, which created two geographical sets: Coastal (Adriatic) Croatia and Continental Croatia. Data were analyzed using univariate statistics and multivariate analysis as exploratory factor analysis, cluster analysis and principal component analysis. Findings – The results in...

Collective Wine Export Promotion in Transitional Countries: The Case of Croatia

This article aims to analyze the present situation in the wine sector by identifying the interest of producers regarding collective export promotion, exploring the reasons why producers should join the export promotion fund, and identifying benefits of the export promotion fund, based on the Croatian case study. Data were analysed using univariate statistics, bivariate correlations, and factor analysis. In the work quantitative and qualitative research methods were used: SWOT analysis and quantitative data analysis. The study contributes to greater knowledge of the willingness of Croatian wine producers for association and it is the first research about collective export promotion of wine in Croatia.

Application of Fuzzy Logic in Diet Therapy - Advantages of Application

Computing, in its usual sense, is centred on manipulation of numbers and symbols. In contrasts, computing with linguistic variables is a methodology in which the object of computation are words and propositions drawn from a natural language, e.g., significant increase in price, small, large, far from recommendations, etc. Computing with words is inspired by the remarkable human capability to perform a wide variety of physical and mental tasks without any measurements and any computation. A basic difference between perception and measurements is that, in general, measurements are crisp whereas perceptions are fuzzy. Instead of Boolean logic, fuzzy logic uses a collection of fuzzy variables defined by membership functions and inference rules. Most of traditional tools for formal modelling, reasoning, and computing are crisp, deterministic, and precise in character. This methodology is a part of mathematical theories of artificial intelligence. Human nutrition, notably the diet evaluation, considering the daily intake of energy and nutrients, is often explained by computing with words, for instance the final conclusion regarding an analysed diet plan can result with phrases as: “the intake of Na should be considerably reduced” or “the consumption of fruits and vegetables must be increased”. The theory of fuzzy logic was used in the planning and management of expenses in social nourishment concerning also the nutritive structure of meals. Modelling and planning of nourishment includes a number of unspecified characteristics, which are depended on nutrient offer and also on age, gender and profession of a person (concerning the physical activity level) or population group. Some recommended nutrient and energy intakes are given as single numbers (crisp values). But for most nutrients are also given the average requirements (AR), the lowest threshold intake (LTI) and the calculated population reference intake (PRI). These intervals and the values of LTI, AR and PRI do not represent the full reality, which is a continuous transition from critical low intake to adequate intake to excess or even toxic amounts. In this work the daily recommendations as crisp numbers are modelled as fuzzy sets. The daily recommended intake (DRI) for each observed nutrient and energy intake is “softened” by introduction of membership function of fuzzy sets defined for each individual nutrient

Classification and Processing Optimization of Barley Milk Production Using NIR Spectroscopy, Particle Size, and Total Dissolved Solids Analysis

Barley is a grain whose consumption has a significant nutritional benefit for human health as a very good source of dietary fibre, minerals, vitamins, and phenolic and phytic acids. Nowadays, it is more and more often used in the production of plant milk, which is used to replace cow milk in the diet by an increasing number of consumers. The aim of the study was to classify barley milk and determine the optimal processing conditions in barley milk production based on NIR spectra, particle size, and total dissolved solids analysis. Standard recipe for barley milk was used without added additives. Barley grain was ground and mixed in a blender for 15, 30, 45, and 60 seconds. The samples were filtered and particle size of the grains was determined by laser diffraction particle sizing. The plant milk was also analysed using near infrared spectroscopy (NIRS), in the range from 904 to 1699 nm. Furthermore, conductivity of each sample was determined and microphotographs were taken in order to identify the structure of fat globules and particles in the barley milk. NIR spectra, particle size distribution, and conductivity results all point to 45 seconds as the optimal blending time, since further blending results in the saturation of the samples.

Integrated approach for bioactive quality evaluation of medicinal plant extracts using HPLC-DAD, spectrophotometric, near infrared (NIR) spectroscopy and chemometric techniques

ABSTRACT To establish a universal analytical tool that could be used as a bioactive quality determination procedure on medicinal plant extracts, a range of spectrophotometric assays, HPLC, near infrared reflectance spectroscopy and chemometric analysis were employed for determination of the bioactive quality of 16 widely spread medicinal plants. Macro-constituents (total carbohydrates, soluble polysaccharides, proteins, amino acids) and secondary plant metabolites (total phenols, flavonoids, hydroxycinnamic acids, flavons, and flavonols) were determined, and HPLC method for the simultaneous determination of phenolic acids and flavonoids was developed, and its linearity, limits of detection and quantification, precision, and accuracy were validated. The evaluated medicinal plant extracts were characterised by a marked protein (marigold – 4.22 g/kg dw), amino acid (marigold – 61.14 g/kg dw), and carbohydrate content (dandelion – 113.5 g/kg dw), while Lamiaceae plants were distinguished as the predominant sources of polyphenolic bioactives (<2.26 g GAE/L). The developed HPLC method enabled separation of 24 polyphenolic compounds within a short analysis time (30 min) and revealed rosmarinic and chicoric acids as the prevalent polyphenolic constituents. NIR spectroscopy coupled with chemometric analysis of all determined analytical parameters indicated the suitability of NIR analysis for amino acids, carbohydrates, and polyphenols determination in medicinal plant extracts.