The content of potentially antioxidant, anticarcinogenic and antiallergic flavonoid aglycons, quercetin, kaempferol, myricetin, apigenin and luteolin of 45 fruits were determined by RP-HPLC with UV detection. Fresh and dried fruits were purchased in the local markets in Budapest at a period of their most frequent consumption. Total flavonoid content of fruits varied between 0–1000 mg kg –1, the average concentration was about 30 mg kg –1 fresh weight. Quercetin could be detected in most fruits, namely in apples, pear, plums, sweet and sour cherry and berries between 10–53 mg kg –1. Luteolin at a concentration of 20 mg kg –1 was found in melons, apples, kiwi and lemon. Myricetin was in detectable amount in redcurrant, and at very high concentration in some berry fruits (mulberry 453 mg kg –1, raspberry 540 mg kg –1, blackberry 636 mg kg –1, strawberry 994 mg kg –1), and in walnut (4565 mg kg –1). Kaempferol and apigenin were not found in the fruits investigated. None of the five flavonoids was found in some variety of grapes, in peach, pear, banana, orange, grapefruit and tangerine, in nuts such as almond, pistachio, nuts, and in dried fruits such as raisin, date, fig and prunes. These data provide a basis for the evaluation of the average daily intake of Hungarian population and for an epidemiological evaluation of health-promoting effects of flavonoids. __
Authors:K. Delonga, I. Radojčić Redovniković, V. Dragović-Uzelac, V. Mrkić, and J. Vorkapić-Furač
The interest in food with chemoprotective properties has been steadily increasing due to many epidemiological studies indicating the lower probability of acquiring some kinds of cancer (e.g. colon, prostate, breast, cervical) in populations, whose diet includes large quantities of
vegetables. The biologically active compounds in
vegetables are the breakdown products of glucosinolates, including isothiocyanates, nitriles, thiocyanates, indoles and oxazolidinethiones from which indoles and isothiocyanates in particular have been implicated to have anticarcinogenic properties. The object of the present study was to investigate glucosinolates distribution as well as their losses during blanching and cooking in edible parts of white cabbage, cauliflower, kohlrabi and collard. In all vegetable, only indole glucosinolates as precursors of anticarcinogenic compounds were identified, while glucoraphane was not detected. In cauliflower and collard, proportion of indole glucosinolates was more then 90%, followed by kohlrabi (>70%) and white cabbage (>50%). Analysis of glucosinolates losses during blanching and cooking showed substantial decrease in all vegetables. The major losses were observed for cauliflower, around 60%, for cooked vegetable, followed by white cabbage (55%), kohlrabi (53%) and collard (44%). The losses after blanching were approximately 15% less then in cooked vegetables.
Authors:N. Elmnasser, M. Ritz, F. Leroi, N. Orange, A. Bakhrouf, and M. Federighi
Pulsed light is a new method intended for the decontamination of food surfaces using short, high frequency pulses of an intense broad spectrum. The effects of broad spectrum pulsed light on the survival of
SF680 populations on agar and in a liquid medium were investigated during this study. The sterilisation system generated 1.5 J cm
per pulse with eight lamps for 300 μs. In the case of surface-seeded cells, a 7.8, 8.14 and >7.14 log reduction was obtained for
L. monocytogenes, Ps. fluorescens
, respectively, after a single pulse of treatment. Inactivation levels were lower for depth-plated cells: indeed, 10 pulses of treatment achieved 1.6, 2.03 and 4.78 log reductions for
MF37, respectively. After 5 pulses,
exhibited a 4.6 log reduction. Similarly, bacterial cells in suspension treated with 3 pulses were reduced by 0.52, 0.8, 2.07 and 2.05 for
, respectively. No resistance to pulsed light was observed during our experiments.
The content of the potentially health-defensive and disease-preventive flavonoids quercetin, kaempferol, myricetin, apigenin and luteolin of 31 vegetables were determined by RP- HPLC with UV detection. Vegetables were purchased at the local markets in Budapest at a period of their most frequent consumption. Quercetin levels in the edible parts of most vegetables were generally below 10 mg kg &1, except for onions (67&121.5 mg kg &1), lettuce (13.5&35.0 mg kg &1), dill (74.5 mg kg &1), broccoli (15.5 mg kg &1) and spinach (272.2 mg kg &1). Kaempferol was below 30 mg kg &1 except for parsnip (66.4 mg kg &1) and leek (45.8 mg kg &1). Myricetin could only be detected in lettuce, Swedish turnip, parsley and celery leaves, and dill. Detectable amount of luteolin was in radishes, some representatives of Brassica, sweet peppers, celery leaves and spinach while apigenin was only in Swedish turnip, celery root and celery leaves. These data provide a basis for the evaluation of the average daily intake of Hungarian population and for an epidemiological evaluation of health-promoting effects of flavonoids.
Authors:J. Bošnir, D. Puntarić, V. Novosel, I. Klarić, and M. Miškulin
The aim of this study was to determine the residue levels of the organochlorine pesticides in cows’ milk from Karlovac County, Croatia. The study included 48 pooled milk samples: 40 pooled samples of non-processed (raw) milk and 8 pooled samples of processed milk collected in the Karlovac County from May 2003 until April 2004. Organochlorine pesticides DDT and derivates, HCH, lindane, heptachlor and endosulfan were determined using the GC-ECD method. The detection limit was 0.01 μg kg
. The determined amounts of organochlorine pesticides were predominantly and significantly below the Maximum Residue Limit (MRL) set by the European Union and which Croatia has also recently adopted as its standard. The study has confirmed pesticide persistence in milk samples from our country despite the fact that some of them have been banned some thirty years ago, which indicates a high degree of dispersion of this substances in the environment. Taking into account that milk is a foodstuff of high biological value consumed frequently and in large quantities by vulnerable groups of population (children, pregnant women, elderly people), the continued monitoring and control of organochlorine pesticides in milk is therefore of great importance for public health.
Authors:K. Török, L. Hajas, Zs. Bugyi, G. Balázs, and S. Tömösközi
Disorders induced by cereal proteins (e.g. wheat allergy, celiac disease) are widespread in human population. Since their only effective treatment is the avoidance of the problematic proteins, patients have to be familiar with the composition of food products. For checking special foods produced for them, proper analytical methods are necessary. At the moment, in gluten analysis there are no reference methods and reference materials which model real food matrices. During the production and experimental utilisation of our previously developed reference material candidate, numerous questions emerged. As our model product is a real food matrix, interactions can be present between gluten proteins and other macro and micro components. Fat content of the baked cookies is almost 20%, which might affect the results of ELISA measurements. The detectable gluten content is significantly increasing after the defatting procedure, as a pre-treatment of samples. Moreover, baking is a common food processing step that might modify the structure of gluten proteins leading to denaturation and aggregation. In the soluble protein fraction the amount of low molecular weight proteins increases, while that of high molecular weight proteins decreases during the baking procedure.
The world has finite water resources, which are under increasing stress as the human population and water demand per capita both increase. These problems are not new but are now becoming more widespread and their impacts more devastating. This has provided additional impetus for the search for solutions to problems arising from the mismatch between demand and supply in terms of water quantity, quality and timing. Increasing water productivity has been identified as one of the global challenges that require urgent attention.This study examines approaches to assessing water productivity in agriculture. Many studies have been carried out on agricultural water productivity [WP] in the world, where most of these studies, specifically in relation to water and food policies of WP, are considered in regional or watershed scale. There are many methods of calculating evapotranspiration (ETc) on regional scale but remote sensing technique since last decade of this century has become more popular one. SEBAL algorithm was used in this research to calculate ETc. Last versions of SEBAL algorithm can calculate aerial crop biomass and then can calculate crop water productivity. In this research, five cloudless MODIS and AVHRR images from Qazvin plain which is located in the center of Iran were selected, and then water productivity calculated with SEBAL algorithm, which runs with ENVI and ILWIS models on MODIS and AVHRR images. Amount of ETc, which was estimated from SEBAL, compared with lysimeter data with r-square [R2] value of 0.9 for MODIS images and 0.81 for AVHRR images. Estimated ETc was higher than lysimeter data in AVHRR and lower than it in MODIS images. Water productivity was estimated 0.76 and 1.03 kg/m3 in MODIS and AVHRR images respectively, but is 0.9 kg/m3 in lysimeter.
In case of spices or crude drugs of medicinal- and aromatic plant origin, sensory characteristics, especially odour, has great commercial importance. The instrumental sensory analysis the so-called 'electronic nose' has proved to be a significant, new and quick method in chemometry. The sensor signal responses (data recorded by the electronic nose instrument) of the electronic nose were evaluated by statistical methods, including principal component analysis (PCA) and canonical discriminant analysis (CDA) and the combination of these methods by applying the discriminant analysis on the first eight principal components. The aim of this paper is the comparative analysis of the above evaluation methods as data processing tools of the sensor signal response of the electronic nose (chemosensor array). The essential oil of oregano (Origanum vulgare subsp. hirtum) selected line No. 10 was compared to the oil distilled from the selected line No. 11; and dried root samples of lovage (Levisticum officinale) harvested at different times from the two- and three-year-old population, were investigated with electronic nose (NST-3320, AppliedSensor Sweden AB). Principal component analysis, as a first step of the evaluation, did not clearly distinguish either oregano or lovage samples. Further statistical evaluation of the original sensor signal responses of the electronic nose with canonical discriminant analysis improved the separation power of the model. The best separation could be achieved by the combination of the two methods, whereby canonical discriminant analysis was applied to the first eight principal components, which described 99% of the differences. In all cases more than 92%, while in several experiments 100% of cross-validated grouped cases were classified correctly. Based on the results, the application of the electronic nose and the combination of multivariate methods, PCA and CDA, could be an appropriate tool either for identification of cultivar to accelerate selection process or to distinguish crude drugs of different age or different harvesting period.
Competition between a bacteriocinogenic and a non-bacteriocinogenic Lactococcus lactis strain, respectively, and a Listeria monocytogenes strain was studied in two semi-synthetic liquid media at various temperatures. The media used for the study were ST I and modified ST I broth (ST I broth + 1 g l-1 Tween 80). In both media, at 30 °C, a significant cell count reduction (5 log) of L. monocytogenes occurred only when the cell concentration of the bacteriocinogenic competitor reached the level of at least 107 CFU ml-1 required for the production of sufficient concentration of nisin-like bacteriocin. The same phenomenon was also observed when the initial level of the lactic acid bacteria (LAB) was one log higher or lower than that of the Listeria, however, the reduction of Listeria cell count occurred earlier with the higher initial concentration of the LAB. Incubation of the mixed cultures at 20 °C gave similar results but the bacteriocinogenic activity resulted in only a three log decline of the cell count of L. monocytogenes. At 10 °C Lactococcus lactis produced much less bacteriocin than at 30 °C, therefore, a drastic decrease of the Listeria cell count was not observed. Suppression of the Listeria growth was expressed in its decreased maximum population level (i.e. in an earlier appearance of the stationary phase). When the non-bacteriocinogenic Lac. lactis and Listeria were present at the same initial level (approx. 105 CFU ml-1), the Lactococcus did not affect the growth of L. monocytogenes at 30 °C in modified ST I broth.
The objectives of the study were twofold, i.e. to evaluate methodological approaches of analyzed papers and to identify, cluster, and classify barriers to HACCP system implementation using meta-analysis as methodological tool. Hazard Analysis and Critical Control Point (HACCP) is a science-based system of risk management designed to control food safety. HACCP is based on seven basic principles, which present an important tool in combating food borne disease. Articles for analysis were initially selected in the major on-line database for the field, namely “Food Science and Technology Abstract”. Other databases were also used, including Commonwealth Agricultural Bureau and Co-operative Online Bibliographic System and Services. Selection was based on scientific excellence of the journal as well as on the method applied within the study. Main keywords to select appropriate scientific and technical articles were “HACCP”, “barrier” and “implementation”. Main results of methodological inquiry revealed that the most frequent methods used in scientific articles were quantitative ones. Among qualitative methods, the “narrative interview” was used most often, while among quantitative methods survey was used most frequently. Whereas narrative interview enables in-depth analysis of implicit role of individual actor in HACCP system, survey methods estimate frequency distributions of particular behaviours or attitudes in observed population. Lately, when analyzing implicit role of an individual in ensuring food safety, a psychological approach became important. The main goal of methodological analysis is to propose advances in research models that would tackle both qualitative and quantitative issues at the same time and offer new insights into barriers in HACCP system implementation. After analyzing the barriers to efficiency of the system, we identified elements that enabled us to cluster barriers into groups and identify the influence of specific elements on HACCP system efficiency. This paper is offering a novel approach to terminological classification of identified barriers, which will open new dimensions in assuring common language among food safety professionals in the future.