Characterization of several hazelnut (Corylus avellana L.) cultivars based in chemical, fatty acid and sterol composition

Nineteen cultivars of hazelnuts (Corylus avellana L.) collected during the 2001 crop, from Vila Real, Portugal, were analysed for chemical composition, including moisture, total oil content, crude protein, ash, carbohydrates and nutritional value. Fat was the predominant component, ranging from 59.3 to 69.0%. Total oil was extracted and analysed for fatty acid and sterol compositions and oxidative stability. Fatty acid and sterol compositions were determined by Gas–Liquid Chromatography coupled to a Flame Ionisation Detector (GLC/FID). Monounsaturated fatty acids, particularly oleic acid, were predominant (78.7–84.6%). Total phytosterol content ranged from 133.8 to 263.0 mg/100 g of oil. Among the nine sterols identified and quantified, β-sitosterol was the major one with a mean percentage of 83.6%, while Δ⁵-avenasterol and campesterol were the second and the third components of the group with mean values of 6.1 and 5.8%, respectively. Since hazelnut oil can be used in olive oil adulteration, the values obtained were compared with published mean values of olive oils from different geographical origins.     

Changes in pigment profile and surface colour of fig (Ficus carica L.) during drying

In this study, anthocyanins in three fresh fig varieties (Ficus carica L.) cultivated in Turkey were characterised and quantified by HPLC/DAD and HPLC/MS. In addition, the carotenoid composition of Sar?lop and Sar?zeybek, yellow fig varieties, was determined, and then the ripening‐ and drying‐related changes in carotenoids and surface colour of figs were monitored during conventional sun‐drying. Four different anthocyanins, cyanidin‐3‐glucoside, cyanidin‐3,5‐diglucoside, cyanidin‐3‐rutinoside (major anthocyanin) and pelargonidin‐3‐glucoside, were identified in samples. Lutein, zeaxanthin, β‐cryptoxanthin and β‐carotene were carotenoids in yellow fig varieties. Approximately 80% of carotenoid compounds in yellow fig varieties degraded at the end of drying (i.e. seventh day). L (lightness), a (redness and greenness) and b (yellowness and blueness) colour parameters were measured by Hunter Lab system. Great changes in carotenoid composition and surface colour were observed at ripening stage on tree. A significant reduction in L and b values that refers to browning in figs was made in the first 3 days of drying process.     

Water sorption and cooking time of red kidney beans (Phaseolus vulgaris L.): part I – Effect of freezing and drying conditions on water sorption and cooking time

Water sorption and cooking time of kidney beans were determined. The beans were manually harvested at 19.2 ± 0.1% moisture content and stored at ?20 and ?10 °C for about half a year. The beans were further dried at 30, 40 and 50 °C inside a thin‐layer drier for 7.5 h or under room conditions for 4 week. The freezing storage temperature before the beans were dried did not influence their cooking time and water sorption. The saturated kernel volumes decreased approximately 7% after drying. The beans decreased their sphericity during water sorption and had a larger swelling ratio in the thickness direction than in other directions. Lower initial moisture content, especially with a higher drying temperature, decreased water sorptivity and resulted in higher percentage of uncooked kernels if the beans were not soaked before cooking. However, there was no relationship between initial moisture content and uncooked percentage if the beans were soaked before cooking. High drying temperature resulted in hard‐to‐cook (HTC) phenomenon.     

Survival of enterohaemorrhagic Escherichia coli O157:H7 strain in Turkish soudjouck during fermentation, drying and storage periods

Soudjouck (a kind of Turkish sausage) batter was inoculated with Escherichia coli O157:H7 at a level of 10⁵ colony-forming unit (CFUg) and kept overnight at 4°C. After stuffing the soudjouck batter into natural casing, fermentation was carried out at 24±2°C and 90–95% relative humidity (RH) for 3 days with subsequent drying at 22±2°C and 80–85% RH for 5 days. Then, half of soudjouck samples were vacuum-packed in polyethylene bags and the rest were kept open. All samples were stored at 4°C (55% RH) for 3 months. E. coli O157:H7 and lactic acid bacteria counts, moisture contents and pH values of the samples were determined during fermentation, drying and storage periods. Results showed that count of E. coli O157:H7 decreased by 3 log unit during fermentation and drying periods. It was observed that this pathogen survived longer in vacuum-packaged samples (more than 2 months) than non-vacuum samples (more than 1 month).     

Drying characteristics and thermal degradation kinetics of hardness,anthocyanin content and colour in purple‐ and red‐fleshed potato (Solanum tuberosum L.) during hot air drying

Purple‐fleshed potatoes (PFP) and red‐fleshed potatoes (RFP) were dried using hot air. The hardness, anthocyanin content and colour in PFP and RFP during drying were evaluated at 60, 70 and 80 °C. The hardness was characterised by a softening stage in the early drying period, followed by a hardening stage. The times to reach at the transition were 420, 300 and 240 min at 60, 70 and 80 °C, respectively, for PFP, and 480, 360 and 240 min for RFP. However, the moisture content of both PFP and RFP at the transition time was identical at 0.3 (d.b.). The two stages of hardness changes were well described by combining two modified first‐order kinetics models. The activation energy (E_a) for the degradation of anthocyanin in PFP and RFP was 25.12 and 28.43 kJ mol^?1, respectively. The E_a values demonstrated that the thermal sensitivity of PFP was higher than that of RFP.     

Sensory and quality parameters of raw and processed Chicory-Hindbeh,a commonly consumed dark leafy green in Lebanon (Cichorium intybus L.) during frozen storage

This work aimed at assessing the effect of heat treatment and frozen storage on the sensory and chemical properties of chicory with the goal of optimizing the heat pretreatment-storage condition to best preserve the chemical and sensory properties of chicory. Raw, boiled (10 min), blanched (90 °C for 60 s) and steamed (for 20 s) chicory samples were produced and stored at −6 °C, −12 °C or −18 °C for 4 months. Chemical analyses (moisture, ash, vitamin C, peroxidase activity, chlorophyll and color) and sensory evaluation (QDA and hedonic evaluation) were conducted. Treatment significantly influenced all chemical variables (p < 0.001), except for moisture; and so did freezing temperatures for a-value (p < 0.001), chlorophyll-a, peroxidase activity, vitamin C and ash (p < 0.01), total chlorophyll, moisture and b-value (p < 0.05). Differences were obtained for age for all chemical variables (p < 0.001). Treatments affected consumers' acceptability of chicory and QDA showed that boiled chicory was significantly more tender, less chewy and crunchy and needed less time to disintegrate than other samples. PCA showed that PC1 and PC2 separated attributes based on type and intensity of treatments, respectively. It is recommended to use blanching at 90 °C for 60 s and freezing at −12 °C or −18 °C to best preserve the quality of chicory.     

Estimation of freezing storage time and quality changes in hake (Merluccius merluccius, L.) by low field NMR

The potential of low field NMR (LF NMR) as a fast monitoring technique to estimate the quality of hake (Merluccius merluccius) frozen stored at -10°C for up to 6months was evaluated. LF NMR clearly detected three populations of water: water strongly bound to macromolecules (T(2b)), trapped water (T(21)) and free water (T(22)). As storage time increased, and concomitant with an increase in the T(22) and a decrease in the T(21) water populations, the water holding capacity (WHC) and apparent viscosity values decreased and the shear strength increased, reflecting the characteristic loss of juiciness and tougher texture developed by hake during frozen storage. Two mathematical models were constructed: a simple regression using the biexponential analysis of the relaxation times (T(21), T(22)) and amplitudes (A(21), A(22)) and a partial least square regression (PLS) of CONTIN analysis. Both models seemed suitable to estimate the quality of the product.     

Changes in anthocyanin,flavonoid and phenolic acid concentrations during development and storage of coloured potato (Solanum tuberosum L) tubers

Changes in the anthocyanin concentration of coloured potato tubers have been investigated in cultivars with coloured skin and coloured or white flesh. The biosynthesis of anthocyanins coincided with tuber initiation in cultivars with intensely coloured mature tubers and, after a slight increase as the smaller tubers increased in size, anthocyanin concentrations remained relatively constant. Thus, because tubers were increasing in weight, anthocyanin was being synthesised to maintain a more or less constant concentration. In cultivars with less coloured tubers, the developing tubers remained white for a longer time, with anthocyanin concentrations increasing gradually up to a maximum at a certain tuber weight depending on the cultivar. The concentration of flavonoids was lower than that of anthocyanins but followed a similar pattern. Phenolic acid levels were about twice those of the anthocyanins and reached their maximum at a slightly lower tuber weight than anthocyanins and flavonoids. During cold storage (4°C) the anthocyanin concentration in coloured tubers increased, whereas tubers stored at higher temperatures did not show this increase. The increased colour in cold‐stored tubers is discussed in terms of its relationship to ‘cold sweetening’ and the increased concentration of sugars in cold‐stored tubers. The distribution of anthocyanins altered during tuber development and also during cold storage. In very small developing tubers the anthocyanins appeared first at the stem end of the tuber whilst the bud end remained white. As the anthocyanin concentration increased during tuber development, it increased over the whole tuber, but the concentration at the stem end was always higher than that at the bud end, until the tuber reached maturity, when the concentration became approximately equal at both ends. After cold storage, tubers had a higher concentration of anthocyanin in the bud end than the stem end; the opposite to that found in developing tubers. © 1999 Society of Chemical Industry     

Total volatile basic nitrogen and trimethylamine nitrogen levels during ice storage of European hake (Merluccius merluccius): A seasonal and size differentiation

Whole ungutted European hake (Merluccius merluccius) caught by trawling off the Central Tyrrhenian coast of Italy in winter and in summer were stored in ice. The dynamics of changes of total volatile basic nitrogen (TVB-N) and trimethylamine-nitrogen (TMA-N) levels during ice storage of small- (20 ± 3 cm length) and large-sized (37 ± 6 cm length) hake caught in either season were studied. The TVB-N and TMA-N levels of hake caught in winter remained low (below 20 mg and 3 mg/100 g, respectively) throughout the experiment regardless of the body size. In summer TVB-N and TMA-N levels increased sharply (P < 0.05) during ice storage and at a higher rate in small than in large fish, a fact ascribable to fish exposure to high temperatures first in the water, during trawling, and then in the fishing vessel before ice-boxing. On the basis of the results obtained in this work, it may be concluded that ungutted European hake show a clear seasonal and size differentiation of the evolution of TVB-N and TMA-N during ice storage.     

Monitoring colour,volatiles in the headspace and enzyme activity to assess the quality of broccoli florets (Brassica oleracea L. italica cv. Bellstar and Legacy) during postharvest storage

The research objective was to study whether volatile organic compounds released in the headspace could be used to assess the broccoli quality (Brassica oleracea L. italica cv. Bellstar and Legacy) during postharvest storage (23 °C for 7 days) and correlated with colour change and the activity of peroxidase/POD, ascorbic acid oxidase/AAO and lipoxygenase/LOX. Volatile organic compounds were monitored using PTR‐MS. Methanol had the highest concentration compared with other volatiles released in the headspace that significantly increased during senescence. The methanol concentration was approximately 500 ppbv before the broccoli colour began to change from green to yellow. The concentration of methanol in the headspace increased to 1000–1100 ppbv for Bellstar and Legacy when the colour became yellowish. LOX had high correlation (0.91 and 0.83 for Bellstar and Legacy, respectively) with volatiles for both cultivars, but not for POD. Methanol production is proposed as the best volatile marker to assess the broccoli quality.     

Reductions in flesh discolouration and internal morphological changes in Nanhui peaches (Prunus persica (L.) Batsch, cv. Nanhui) by electrolysed water and 1-methylcyclopropene treatment during refrigerated storage

The effects of electrolysed water (EW) and EW in combination with 1-methylcyclopropene (EW/MCP) on flesh discolouration of Nanhui peaches (Prunus persica (L.) Batsch, cv. Nanhui) were examined during storage at 2°C. Changes in flesh colour, ethylene production, membrane permeability, malondialdehyde (MDA), total phenolic contents and the activities of polyphenol oxidase (PPO) and peroxidase (POD) were assayed periodically after harvest and during 44days of storage. The internal morphological characteristics of Nanhui peaches were monitored using magnetic resonance imaging (MRI) at the beginning and end of storage. These data revealed that the EW/MCP treatment is more effective than the EW treatment for decreasing ethylene production and maintaining fruit cell membrane integrity, delaying increases in MDA and total phenolic contents, and lessening changes in PPO and POD activities and the internal morphology of peaches. Each of these effects contributes to suppressing flesh discolouration and maintaining the quality of Nanhui peaches during storage.     

The interactive effects of irrigation,nitrogen fertilisation rate,delayed harvest and storage on the polyphenol content in red grape (Vitis vinifera) berries: A factorial experimental design

Polyphenol concentrations, including anthocyanidins, flavonols, flavan-3-ols and stilbenes, were quantified by liquid chromatography/mass spectrometry in two cultivars of red grapes for daily consumption, which were subjected to different kinds of water supply and nitrogen fertilisation rates. Samples from the same vineyards were also analysed after a 6 week storage in a refrigerator and 6 week delayed harvesting. Berry skins and seeds were analysed separately.     

Physico‐chemical and sensory attributes in conjunction with multivariate analysis of two potato (Solanum tuberosum L.) cultivars after 90 days of storage: an exploratory authentication study

Two cultivars of potato (Spunta and Agria), were studied in terms of their physico‐chemical and sensory characteristics. These cultivars were cultivated in three geographical regions of Greece (Macedonia, North Greece; Thessaly, Central Greece; Peloponnese, South Greece) and were stored for 90 days after harvesting. The physico‐chemical characteristics of the tubers determined, were pH, total acidity, firmness, dry matter and content in Ν, in Κ, P, Cu, Mn, Zn and Fe. The sensory characteristics measured for raw tubers of potato after storage, were skin colour, skin brightness, internal colour, surface roughness, odour intensity, moistness, surface wrinkling and stains while the sensory characteristics measured for the boiled tubers of potato were odour intensity, moistness, special taste, sweet taste, aftertaste persistence, metal taste, pastiness, mastication, flavour intensity, elasticity and overall acceptability. The application of multivariate analysis (principal component analysis, cluster analysis and discriminant analysis), revealed a variety of relations between the various parameters and resulted in satisfactory grouping either per geographical region or per cultivar.     

A systemic approach to qualitative changes in the stored-wheat ecosystem: Prediction of deterioration risks in unsafe storage conditions in relation to relative humidity level, infestation by Sitophilus oryzae (L.), and wheat variety

A multidimensional laboratory trial was carried out to identify the primary causes of changes in quality traits in the stored-grain ecosystem to reveal critical storage condition boundaries that may endanger grain quality retention. Qualitative criteria were followed on grain batches from 3 wheat varieties which were stored for 160 d at temperature of 22-23 °C, at two different relative humidities, and with or without infestation by the rice weevil Sitophilus oryzae, to build a multivariate data matrix. The interactions between biotic deteriorative factors and qualitative trait changes were explored through a principal component analysis (PCA). From the Pearson’s product moment correlation matrix, it was observed that the variables that correlated significantly with insect and fungal species dynamics were: moisture content, hL mass, seed viability, and fat acidity of extracted whole flour. Four factors explained the major part of the variance: storage duration, moisture content, hidden insect infestation density, and fungal contamination level. The rate of increase of the insect population was significantly different between varieties. PCA revealed that the significant difference in qualitative deterioration pattern observed between the three varieties was not related to their hardness but rather to a different relationship between the grain and relative humidity. Germination rate was the first quality factor to decline during the storage period. The technological properties of flour extracted from each variety were not affected before insect population density exceeded 1000 adult insects per kg. The rate of qualitative changes induced by the biotic deterioration factors was processed into a “biodeterioration susceptibility index” (BSI) according to the safe storage time assessed in the present study. This index may be used in IPM approaches to predict the susceptibility of a particular wheat variety to insect and fungal damage during long-term storage.