Terezija Golob

Dietary fibre content of dry and processed beans

Abstract Common beans ( Phaseolus vulgaris L.) are a good source of protein, vitamins, minerals and especially dietary fibre. As beans are never eaten raw, the effects of soaking, cooking, soaking–cooking and canning on soluble, insoluble and total dietary fibre contents of beans are studied. Total dietary fibre content was determined by enzyme-gravimetric method. The fraction of insoluble dietary fibre was corrected for the content of resistant starch, determined as part of the total starch in insoluble fibre. The results indicate that thermal processing decreased the insoluble fibre content, and consequently the total dietary fibre content of beans. Soaking and cooking of beans significantly ( P ⩽0.05) increased the resistant starch content. The data on dietary fibre content of processed food are much more relevant than those of raw food. Thus food composition tables should contain as much data on processed food as possible.

Nutrient Content in Buckwheat Milling Fractions

ABSTRACT Buckwheat seeds (Fagopyrum esculentum Moench) were milled into 23 fractions: seven fine flours, three coarse flours, four small semolina, two big semolina, six bran, and one husk fraction. A considerable variation in gross chemical composition was found among the milling fractions. The protein content varied from 4.4 to 11.9% (db) in flours and from 19.2 to 31.3% in bran fractions; starch varied from 91.7 to 70.4% in flours and from 42.6 to 20.3 in bran. The percentage of soluble dietary fiber contained in total dietary fiber was higher in flours than in semolina and bran fractions. Ash, Fe, P, tannin, phytate content, and color were also investigated. A unique distribution of phytate was found in starch. Correlation is significantly positive in husk, bran, and semolina fractions, while correlation is significantly negative in flour fractions. Depending on technological or nutritional demands, appropriate fractions may be chosen to achieve the desired end-use product.

Carbon and nitrogen natural stable isotopes in Slovene honey: adulteration and botanical and geographical aspects.

Isotope parameters (δ(13)C(honey), δ(13)C(protein), δ(15)N) were determined for 271 honey samples of 7 types (black locust, multifloral, lime, chestnut, forest, spruce, and fir honeys) from 4 natural geographical regions of Slovenia. Carbon and nitrogen stable isotope ratios were measured to elucidate the applicability of this method in the identification of the botanical and geographical origin of honey and in honey adulteration. Only 2.2% of the samples were adulterated according to the internal standard carbon isotope ratio analysis method. Botanical origin did not have any major influence on the honey isotope profiles; only black locust honey showed higher δ(13)C values. Some differences were seen across different production years, indicating that the influence of season should be further tested. Statistical and multivariate analyses demonstrated differences among honeys of various geographical origins. Those from the Alpine region had low δ(13)C (-26.0‰) and δ(15)N values (1.1‰); those from the Mediterranean region, high δ(13)C (-24.6‰) and medium δ(15)N values (2.2‰); those from the Pannonian region, medium δ(13)C (-25.6‰) and high δ(15)N value (3.0‰); and those from the Dinaric region, medium δ(13)C (-25.7‰) and low δ(15)N values (1.4‰).

Chemical changes in extra virgin olive oils from Slovenian Istra after thermal treatment

Changes in the physico-chemical parameters of extra virgin olive oils after heating for 142h at 100°C with an air flow 10L/h were investigated. The experimental study was carried out on the two predominant olive cultivars in Slovenian Istra - cv. Istrska belica and cv. Leccino. The data obtained showed that oils from Istrska belica were more stable than those from Leccino. Peroxide values and spectrophotometric data showed higher amounts of oxidation products in oils from Leccino than in those from Istrska belica. After thermal treatment fatty acid composition was changed more in Leccino oils; particularly the amounts of polyunsaturated fatty acids dropped significantly, while α-tocopherol was completely depleted in all samples. The content of total biophenols decreased from 598mg/kg to 241mg/kg in Istrska belica oils and from 391mg/kg to 176mg/kg in Leccino oils. HPLC data showed that transformation of secoiridoid biophenols to the simple biophenols, tyrosol and hydroxytyrosol took place.

The Slovenian food composition database.

The preliminary Slovenian food composition database was created in 2003, through the application of the Data management and Alimenta nutritional software. In the subsequent projects, data on the composition of meat and meat products of Slovenian origin were gathered from analyses, and low-quality data of the preliminary database were discarded. The first volume of the Slovenian food composition database was published in 2006, in both electronic and paper versions. When Slovenia joined the EuroFIR NoE, the LanguaL indexing system was adopted. The Optijed nutritional software was developed, and later upgraded to the OPEN platform. This platform serves as an electronic database that currently comprises 620 foods, and as the Slovenian node in the EuroFIR virtual information platform. With the assimilation of the data on the compositions of foods of plant origin obtained within the latest project, the Slovenian database provides a good source for food compositional values of consistent and compatible quality.

Use of HPTLC for Quantitative Evaluation of Inulin in Food Products

HPTLC and HPLC—MS methods have been developed for quantitative determination of inulin in food products. Samples were applied to silica gel HPTLC plates and developed three times, twice with n-propanol—acetone—water, 45 + 30 + 25 (v/v), and the third time with n-propanol—acetone—water, 50 + 40 + 10 (v/v). Total development time was 150 min. Dried plates were dipped into DAP reagent for 10 s. After heating colored spots of the saccharides appeared. Quantitative evaluation of the colored spots was performed in transmission mode by means of a flatbed scanner and densitometer. The precision of measurements for the main inulin fractions was ±6.0%; the limit of quantitation (LOQ) varied from 0.1 to 1 μg per spot; and the ‘linear’ working range was between 0.5 and 4.0 μg per spot. The method was tested on real samples.

Functional and Nutritional Properties of Different Types of Slovenian Honey

Honey, a natural substance traditionally used as a sweetener, is a remarkably complex food. Besides the main components carbohydrates and water it also contains several minor compounds with biological activity. In this chapter functional and nutritional properties of honey, known to be dependent on its botanical and also geographical origin, are presented. Through reported analytical data emphasis is given on Slovenian types of honey.

Elemental Composition of Different Slovenian Honeys Using k0- Instrumental Neutron Activation Analysis

The botanical origin of seven types of Slovenian honey was investigated by analysis of their elemental content using k0-instrumental neutron activation analysis. A total of 28 representative samples were collected from beekeepers all over Slovenia in 2 consecutive years. Nineteen of the 37 elements measured were present in amounts above their LOD. The present study suggests that the determination of only alkali elements might be sufficient for the classification of Slovenian honeys according to their botanical origin. Linden and multifloral honeys can be differentiated on the basis of Na content. The differentiation of forest, spruce, and fir honeys is possible on the basis of differences in Cs, K, and Rb content. The difference between Na and Rb content can be used as a discriminating tool between light and dark honeys, because light honeys (black locust, linden, and multifloral) contained more Na than Rb, whereas it was the opposite for dark honeys (chestnut, forest, spruce, and fir). Statistically significant correlations were found between K and Rb and between K and Cs content. This study represents a considerable step in filling the knowledge gap concerning both the determination of elements present in low concentrations and the botanical origin of Slovenian honey.

Extra Virgin Olive Oil and Table Olives from Slovenian Istria

Olive oil production has a long tradition in Slovenian Istria, and extra virgin olive oil from the region with protected designation of origin (EDOOSI ZOP) is the first Slovenian agricultural product to be registered at the European level, while table olives from Slovenian Istria avail of a protected designation of origin at national level. EDOOSI ZOP has been produced from different olive varieties or from a single olive variety grown in the area of Slovenian Istria. The blended olive oil is characterised by a specially bitter and piquant taste resulting from the fact that it contains at least 30 % of ‘Istrska belica’ olives. In Slovenian Istria, table olives are usually processed using the traditional production technology that involves initial debittering in water for 10–20 days, which is replaced every 2 days, and fermentation in a brine solution. The table olives produced are lightly sour, bitter and salty and are characterised by a good separation between flesh and stone. The flesh of ‘Storta’ table olives, a variety that is very popular among consumers, easily detaches from the stone.