Lajos Helyes

Effect of natural light on surface temperature and lycopene content of vine ripened tomato fruit

Indeterminate round type tomato (Lycopersicon esculentum Mill.) grown on a supporting trellace system in the field was used to determine the correlation between light exposure and the surface temperature and lycopene content of tomato fruit. The positive correlation between solar radiation and surface temperature was stronger (R2 = 0.87) on non-shaded (NS) than on shaded (SF) (R2 >= 0.79) tomato fruits. There was strong negative correlation (R2 = 0.95) between surface temperature and lycopene content of tomato fruits. Increasing solar radiation and temperature explained the lower content of lycopene content and therefore the loss of nutritional quality of the non-shaded tomato fruits. Key words: Tomato, fruit surface temperature, lycopene

Effect of irrigation on yield parameters and antioxidant profiles of processing cherry tomato

A two-year (2010 and 2011) open field experiment was conducted to study the effect of drip irrigation and seasonal variation on the yield parameters and main bioactive components, carotenoids (mainly all trans, cis lycopene, and β-carotene), polyphenols (chlorogenic acid, caffeic acid, gallic acid, quercetin, rutin, naringin, etc.), and tocopherols of processing Strombolino F1 cherry tomatoes. The irrigated plants (STI) gave a higher marketable yield (61% and 101% respectively), and rain fed plants showed a yield loss. Water supply had a strong positive (R2=0.98) effect on marketable yield in 2011, but weak (R2=0.69) in 2010. In both years, the antioxidant concentration (all carotenoids, total polyphenols, tocopherols) showed a decrease with irrigation. Water supply affected the composition of carotenoids to a considerable extent. The optimum water supply treatment gave a lower proportion of lycopene than the rain fed control (STC) treatment. We observed significant negative correlation between rutin concentration and irrigation. The α-tocopherol concentration was significantly higher in STC treatments. Irrigation negatively influenced antioxidant concentrations of cherry tomato fruits, but higher yield could account for the concentration loss of individual fruits by higher antioxidant production per unit area.

HPLC Analysis of Carotenoids from Tomatoes Using Cross-Linked C18 Column and MS Detection

This study was conducted to analyze carotenoids from tomatoes by high-performance liquid chromatography using reversed-phase C18 silica having cross-linked end-capping with diode array and mass spectrometric detection. An efficient gradient elution system was developed to achieve good and reliable separation of both major and minor carotenoids as well as their isomers. Resolution of lycopene, β-carotene and their isomers was 0.91-3.97 and 1.02-2.86 with cross-linked and conventional C18 column, respectively. The % recovery for zeaxanthin, lycopene and β-carotene was found to be in the range of 89-97%. Limits of detection and quantification of 19.44 and 64.79 ng/mL for zeaxanthin, 15.6 and 52.4 ng/mL for lycopene and 8.28 and 27.61 ng/mL for β-carotene were determined. More carotenoid compounds could be separated and detected with the new method as compared with conventional C18 column. Hyphenation of HPLC with photodiode array and mass spectrometry detectors assisted in detection of tetra-dehydrocarotenoid and fatty acid diesters of xanthophylls in tomato products. Content of all-trans-lycopene, β-carotene and total carotenoid in different industrial tomatoes tested was found to range between 41.87 and 84.65, 0.89 and 1.50 and 53.22 and 112.60 µg/g fresh weight, respectively.

Estimation of antioxidant components of tomato using VIS-NIR reflectance data by handheld portable spectrometer**

Abstract Processing tomato production represents an important part of the total production of processed vegetables in the world. The quality characteristics of processing tomato, important for the food industry, are soluble solids content and antioxidant content (such as lycopene and polyphenols) of the fruit. Analytical quantification of these components is destructive, time and labour consuming. That is why researchers try to develop a non-destructive and rapid method to assess those quality parameters. The present study reports the suitability of a portable handheld visible near infrared spectrometer to predict soluble solids, lycopene and polyphenol content of tomato fruit puree. Spectral ranges of 500-1000 nm were directly acquired on fruit puree of five different tomato varieties using a FieldSpec HandHeld 2™ Portable Spectroradiometer. Immediately after spectral measurement, each fruit sample was analysed to determine soluble solids, lycopene and polyphenol content. Partial least square regressions were carried out to create models of prediction between spectral data and the values obtained from the analytical results. The accuracy of the predictions was analysed according to the coefficient of determination value (R2), the root mean square error of calibration/ cross-validation.

Effect of environmental conditions and water status on the bioactive compounds of broccoli

Four experiments were carried out in 2010 and 2011 to determine how cultivation period (spring or autumn), harvest season (summer or autumn), and plant water status (irrigated or rainfed) influenced content and composition of broccoli cultivar Parthenon F1 with respect to sulforaphane and phenolics under field conditions in Gödöllő, Hungary. Sulforaphane content was significantly higher in the autumn harvests, regardless of irrigation treatments. Harvest season also influenced total phenolics content, with the highest values occurring in the spring season. Harvest season also affected trolox equivalent antioxidant capacity (TEAC) and this capacity was also the greatest in spring. Caffeic acid glucoside was a major phenolics component in both spring and autumn season harvests. The season and irrigation related changes in other phenolic component contents were also characterised in this study.

HPLC Determination of Capsaicinoids with Cross-Linked C18 Column and Buffer-Free Eluent

A simple and efficient high-performance liquid chromatographic method was developed and validated for the separation and determination of capsaicin and its major dihydro- and homoderivatives in spice paprika products in 20 min with fluorescent and 35 min with mass-spectrometric detection. The separation was performed on reversed-phase chromatographic adsorbent of cross-linked endcapping with eluent consisting of 1:1 acetonitrile-water or acetonitrile-0.1% formic acid under isocratic conditions. Excellent separation of all the major and minor capsaicinoids with resolution index between 1.08 and 7.34 was achieved. The detection and quantification limits of capsaicinoids in standard material solutions were between 2 and 10 ng/mL. The lowest detectable amount of capsaicin, with fluorescent detection, was found to be <1 µg/g non-pungent spice paprika powder. The naturally occurring capsaicinoids could be distinguished from the non-capsaicinoids compounds appeared on liquid chromatography-fluorescence profile of extract from drastically processed paprika by applying mass spectroscopic detection. Hungarian spice paprika were evaluated as mild to very hot (capsaicinoid content: 334-1,660 µg/g) and chili products as very or extremely hot products (1,543-2,818 µg/g).

Carotenoid determination in tomato juice using near infrared spectroscopy

Abstract A rapid non-destructive method for profiling tomato carotenoids was developed using NIR spectrometry. One hundred and twenty tomato samples were produced at the Experimental Farm of Szent István University in Gödöllő (Hungary). The sample preparation was based on homogenization. The mixed samples were scanned with a diode array Perten DA7200 NIR Analyzer (950-1650 nm) and analyzed by high performance liquid chromatography. The calibration was based on partial least squares regression with cross-validation. The performance of the final model was evaluated according to root mean square error of cross-validation. The results indicate that the main carotenoid components were accurately predicted. The correlation between the NIR measurement and the β-carotene content of tomatoes was adequately high [R2CV = 0.89; root mean square error of cross-validation = 0.174 μg g−1]. The NIR method was also performed for the determination of the all-trans lycopene content (R2CV = 0.75; root mean square error of cross-validation = 6.88 μg g−1). It can be concluded that the diode array NIR spectrometer has the potential to be used for the determination of the main carotenoids of tomatoes.

Evaluation and comparison of open source program solutions for automatic seed counting on digital images

ImageJ, CellProfiler, P-TRAP and SmartGrain evaluated for seed counting from digital images.ImageJ seed counting macro evaluated with RenyiEntropy threshold.Results differ, firstly by image-analysis program and secondly by crop species.CellProfiler and P-TRAP showed suitable performance for seed counting.Benchmark showed lowest time required by SmartGrain and longest by P-TRAP. Seed number quantification is an essential agronomic parameter conducted mostly manually or by mechanical counters, both with obvious limitations. Digital image analysis provides a reliable and robust alternative to accurately calculate many biological features. This study presents and evaluates the performance of four open-source image-analysis programs i.e. ImageJ, CellProfiler, P-TRAP and SmartGrain to count crop seeds from digital images captured by camera and scanner. It also evaluates ImageJ program for automated seed counting using macro containing RenyiEntropy threshold algorithm. Digital images of cereal crop seeds were acquired i.e. wheat, barley, maize, rye, oat, sorghum, triticale and rice. All images contained 200 seeds per image present in an area of approx. 1400cm2. RenyiEntropy threshold increased the seed count accuracy of ImageJ from digital camera images. Generally, seed counts from digital camera images of all crops were accurate, but software-crop combination had significant (p<0.05) difference from reference value. Among image analysis programs, ImageJ produced mostly higher seed count across all observed crops than other programs. Mean seed counts from scanned images of maize were observed only by CellProfiler and P-TRAP, with other programs inappropriate due to high inaccuracy. These results suggest CellProfiler as a reliable image analysis program for seed counting from digital images. Benchmark test was also performed to compare speed of analysis. The automated seed count produced by image analysis programs described here allows faster, reliable and reproducible analysis, compared to standard manual method. To our knowledge this is the first study on using CellProfiler program for crop seed counting from digital images.

Determination of Polyphenols, Capsaicinoids, and Vitamin C in New Hybrids of Chili Peppers

Six hybrids were subjected to chromatographic analyses by HPLC for the determination of phytochemicals such as capsaicinoid, polyphenol, and vitamin C. The dynamics of ripening of 4 of the hybrids were also characterised. Seven capsaicinoids could be separated and determined; the major compounds were nordihydrocapsaicin, capsaicin, and dihydrocapsaicin, while homocapsaicin and homodihydrocapsaicin derivatives were detected as minor constituents. Capsaicin content ranged between 95.5 ± 4.15 and 1610.2 ± 91.46 μg/g FW, and the highest value was found in Bandai (C. frutescens) at the green ripening stage. The major capsaicinoids had a decreasing tendency in Bandai and Chili 3735 hybrids, while no change was observed in Beibeihong and Lolo during ripening. Nine polyphenol compounds were detected including 8 flavonoids and a nonflavonoid compound in the pods of all hybrids. The major components were naringenin-diglucoside, catechin, and vanillic acid-derivative and luteolin-glucoside. Naringenin-diglucoside ranged from 93.5 ± 4.26 to 368.8 ± 30.77 μg/g FW. Except vanillic acid-derivative, dominant polyphenols increased or remained unchanged during ripening. As for vitamin C, its content tended to increase with the advance in ripening in all hybrids included in this study. The highest value of 3689.4 ± 39.50 μg/g FW was recorded in Fire Flame hybrid.

The simultaneous determination of capsaicinoids, tocopherols, and carotenoids in pungent pepper powder

ABSTRACT From nutritional points of view, carotenoids, capsaicinoids, and tocopherols are valuable constituents in pungent peppers. A rapid and reliable high performance liquid chromatography (HPLC) method for the simultaneous determination of phytonutrients in spice red peppers and chili products was developed and validated. The method included simultaneous detection by fluorescence and diode-array detectors. The major capsaicinoids, two tocopherols and 43 carotenoid components, were simultaneously separated, detected, and identified in the appointed pepper powder (containing Capsicum annuum and Capsicum frutescens) for method validation. The separation was performed on a Nucleosil C18 reverse phase column and optimized gradient elution. Resolution ranged between 0.96 and 1.46 with the highest values corresponding to γ-tocopherol and α-tocopherol. The limits of detection and quantification of target compounds ranged between 18.77 and 148.08 ng mL−1. Recoveries were between 89.83–100.26 and 79.72–88.86% when standard materials were spiked at low and high amounts, respectively. The most sufficient extraction of the different phytonutrients was achieved by mixture of methanol and acetone, although it was only slightly better than the mixture of methanol and acetonitrile. These results suggest that the developed method could be used for rapid, one-step determination of a wide range of phytonutrients in chili and pepper powders. GRAPHICAL ABSTRACT