Dessert and crab apple seeds as a promising and rich source of all four homologues of tocopherol (α, β, γ and δ)

Tocochromanols composition in apple seeds, obtained as a by-product during the fruit salad and juice production, of twelve varieties - seven crab apple (‘Kerr’, ‘Kuku’, ‘Quaker Beauty’, ‘Riku’, ‘Ritika’, ‘Ruti’ and K-8/9-24) and five dessert apples (‘Antej’, ‘Beforest’, ‘Kent’, ‘Sinap Orlovskij’ and ‘Zarja Alatau’) were studied. Tocopherols and tocotrienols were isolated using the micro-saponification method of high precision and accuracy and they were analysedanalysed by rapid RP-HPLC/FLD and RP-UPLC-ESI/MSⁿ. Four tocopherols, with predominance of homologues α and β, were detected in each tested sample. The seeds from two apple cultivars ‘Antej’ and ‘Beforest’ were characterized by unique and similar ratios of all four tocopherol homologues α:β:γ:δ (1.7:1.5:1.3:1.0 and 2.1:2.0:1.3:1.0, respectively). The concentration range of individual tocopherol homologues (α, β, γ and δ) in apple seeds were as follows: 17.22–25.79, 7.53–29.05, 0.61–13.82 and 0.16–10.79 mg/100 g dry weight basis (dwb), respectively. Moreover, three tocotrienols (α, β and γ) were identified in lesser amounts (0.02–0.74 mg/100 g dwb). Use of apple seeds to isolate tocopherol homologues can ensure better environmental sustainability and effective use of natural plant material.     

DMA thermal analysis of different parts of potato tuber

Dynamic mechanical analysis (DMA) was applied to three potato tissues (‘cortex’, ‘pith’, and ‘side’ surface) of two cultivars (more waxy ‘Nicola’ and more mealy ‘Saturna’) in temperature scans in the range 30–90 °C and constant air humidity of 90%. The obtained scans indicate peaks in both storage and loss module of elasticity (SM and LM, respectively) at temperatures higher than 70 °C – so called ‘starch’ peak (SP) – as was observed previously. The peak value increase with increasing potato dry matter (DM) content, below DM content approximately 14% no SP is observed (‘Nicola pith’). Slope analysis of the basic parameters: SM, LM, and loss tangent (LT) was performed and further characteristic points on the temperature plots were found: (i) in temperature range A (30–40 °C) maximum of SM and LM and minimum of LT, (ii) in temperature range B (40–50 °C) minimum of SM and LM slopes corresponding to point of inflection on SM-T and LM-T plots, (iii) at about 50 °C, big peak in LT in side tissue only, (iv) at about 70 °C just prior the ‘starch’ peak, big peak in LT that is more marked in ‘pith’; this peak denoted as ‘I’ influenced the ‘starch’ peak ‘II’. It was found that both cultivar and part of the tuber influences the DMA temperature plots.     

Discrimination of European wheat varieties using near infrared reflectance spectroscopy

Near infrared reflectance (NIR) spectroscopy combined with chemometrics was used to discriminate wheat varieties. A total of 249 samples of different wheat varieties from the 2003–2004 harvest were used to develop the best discriminant equation, by applying various scatters and mathematical treatments in the range of 400–2500 nm. Wheat varieties from Spain were ‘Sarina’, ‘Bolero’, ‘Berdún’, ‘Soisson’, ‘Chamorro’, ‘Artur Nick’, ‘Berdun’, ‘Marius’, ‘Anza’, ‘Kalifa’, and wheat varieties from France were ‘Galibier’ and ‘Quality’. The equation developed with the highest accuracy had an applied scatter of weighted multiplicative scatter correction, a math treatment of 2, 15, 8 (order of derivative, gap data points over which the derivative was taken, number of data points used in performing average smoothing). The percentage of correctly identified varieties was 99.5% for the calibration sample set and 94% for the validation sample set. The results demonstrated the usefulness of NIRS combined with chemometrics as a rapid method for discrimination of European wheat varieties. Although the application of the discriminant equation developed for the 2003–2004 harvest yielded a high rate, further test measurements are necessary to evaluate the robustness of the equation.     

Tannin profiles of Vitis vinifera L. cv. red grapes growing in Lisbon and from their monovarietal wines

The tannin profiles of five grape (Vitis vinifera L.) varieties ‘Touriga Nacional’, ‘Trincadeira’, ‘Castelão’, ‘Syrah’ and ‘Cabernet Sauvignon’ and the profiles of their red monovarietal wines from their 2004 and 2005 vintages were studied. Depending on the variety, the polymeric fractions represented 77–85% in seeds and 91–99% in skins. The distribution of the mean degree of polymerisation (mDP) of the proanthocyanidins ranged from 2.8 to 12.8 for seeds and from 3.8 to 81.0 for skins. In the monovarietal wines, the distribution of the mDP of the proanthocyanidins ranged from 2.1 to 9.6. Of the total proanthocyanidins the polymeric fraction represented 77–91% in vintage 2004 and 82–95% in vintage 2005. The wine proanthocyanidins of Trincadeira and Cabernet Sauvignon showed similar tannin profiles in each vintage. After six months of storage, noticeable decreases in total proanthocyanidins concentration were measured. These were accompanied by slight decreases in prodelphinidin percentages but the percentage of galloylation and mDP remained similar.     

HPLC–MS identification of phenols in hazelnut (Corylus avellana L.) kernels

In whole hazelnut kernels, as the main product of hazelnut (Corylus avellana L.), phenols were analysed in 20 hazelnut cultivars by high-performance liquid chromatography–tandem mass spectrometry (HPLC–MS). Twenty-three compounds from different phenolic groups were detected, and 15 of them were identified. In hazelnut kernels, these substances were detected: nine flavan-3-ols, two benzoic acids (gallic and protocatechuic acid), three flavonols and phloretin glycoside. Total phenol concentrations ranged from 70 to 478 mg gallic acid equivalents per kg hazelnut kernels. A high content level of total phenols was observed in the ‘Tonda Gentile delle Langhe’ and ‘Lewis’ cultivars, which was followed by the ‘Corabel’, ‘Fertile de Coutard’, ‘Daria’ and ‘Tonda Gentile Romana’ cultivars. Similarly, the highest antioxidative activity, measured by employing DPPH-antiradical assay, was also found in the ‘Tonda Gentile delle Langhe’ cultivar, followed by the ‘Fertile de Coutard’.     

Comparison of volatile components in fermented soybean pastes using simultaneous distillation and extraction (SDE) with sensory characterisation

In this study, the volatile compounds in nine fermented soybean pastes were extracted and analysed by simultaneous steam distillation and extraction (SDE) and gas chromatography–mass spectrometry (GC–MS), respectively. A total of 91 volatile components were identified. The differences in volatiles were observed by applying principal component analyses (PCA) to GC–MS data sets. Most of the samples did not show apparent groupings; however, a three sample clustering (CJW, SIN and HAE) was observed for pastes made by Aspergillus oryzae inoculation. From the PCA of the sensory data, samples are primarily separated along the first PC (explained 68% of the total variance), between samples like SUJA, CHJA and SOHI with high intensities of ‘briny’, ‘soy sauce’, ‘musty’ and ‘astringent’ and the samples (CJW and SIN) with intense levels in ‘sweet-grain’, ‘sweet’ and ‘MSG’ attributes. The individual concentrations of volatile compounds such as isoamyl acetate, furfuryl alcohol, maltol, pyrazines, 1-octen-3-ol and 2-methoxy-4-vinyl phenol corresponded well to the intensities of related sensory attributes by the correlation analysis.     

Volatile characteristics of 50 peaches and nectarines evaluated by HP–SPME with GC–MS

Using HS–SPME–GC–MS, characteristics of the volatiles of 50 peaches and nectarines representing different germplasm origins were investigated. Ten of these peaches and nectarines were studied in two successive years. Eighty-four compounds were identified. Volatile composition was relatively consistent, but the amount of total volatiles and certain individual compounds varied between years. Moreover, the composition of volatiles and their contents depended on genotypic background and germplasm origin. Total volatiles in wild peaches and a Chinese local cultivar ‘Wutao’ were much higher than in the other groups. All the peaches and nectarines could be classified into four groups by principal component analysis of the volatiles (excluding C₆ compounds): ‘Ruipan 14’ and ‘Babygold 7’ with high contents of lactones, Chinese wild peaches and ‘Wutao’ with high contents of terpenoids and esters, seven cultivars with American or European origins with high content of linalool, and others without characteristic composition of volatiles.     

Volatile compounds evolution of three table grapes with different flavour during and after maturation

Volatile compounds of three different flavour table-grapes, ‘Jingxiu’, ‘Bimeijia’ and ‘Jingya’, were investigated during and after maturation using SPME/GC–MS. All the alcohols and carbonyls, along with most of the C₆ compounds and terpenoids, were evident before veraison, while most of the esters were detected at or after veraison. C₆ compounds increased in the early period of maturation, and then decreased. Most alcohols and carbonyls tended to continuously decrease during ripening. Except for geraniol, terpenoids increased until maturation, then decreased. Some esters continued to increase after maturation. Principal component analysis showed that terpenoids and esters were the characteristic volatiles of ripe ‘Bimeijia’ and ‘Jingya’ grapes, respectively. ‘Bimeijia’ had the highest terpenoid content at maturity, while ‘Jingya’ continued to accumulate some esters after maturation. To achieve berries of full-bodied aroma, ‘Bimeijia’ should be harvested at maturity and ‘Jingya’ should have a delayed harvest. For the neutral grape ‘Jingxiu’, delayed harvest is recommended to reduce the ‘green’ odour.     

Characterisation of onion (Allium cepa L.) by-products as food ingredients with antioxidant and antibrowning properties

Processing and stabilising onion wastes (residues and surpluses of onion) could solve the environmental problem derived from a great onion wastes disposal. Moreover, obtaining stabilised onion by-products as natural antioxidant food ingredients could be advantageous to food industry, not only to improve the use of onion wastes but also to obtain new natural and functional ingredients. The aim of this study was to characterise onion by-products – juice, paste and bagasse – from two Spanish onion cultivars – ‘Figueres’ and ‘Recas’ – that have been stabilised by thermal treatments – freezing, pasteurisation and sterilisation – in order to evaluate the effect of the processing and stabilisation treatment on the bioactive composition, antioxidant activity and polyphenol oxidase (PPO) enzyme inhibition capacity. The results obtained triggered to choose one onion by-product offering better characteristics for its potential development as a food ingredient: source of antioxidant and antibrowning bioactive compounds. In this study it was shown that processing of ‘Recas’ onion wastes to obtain a paste (mixture content) and applying a mild pasteurisation were the best alternatives to obtain an interesting stabilised onion by-product with good antioxidant properties that made useful its use as functional food ingredient.     

Residues of grape (Vitis vinifera L.) seed oil production as a valuable source of phenolic antioxidants

Phenolic compounds of seven grape seed samples originating from mechanical seed oil extraction were identified and quantified by HPLC–DAD before (intact seeds) and after (press residue) the oil recovery process. Total amounts of all identified compounds ranged from 4.81 (‘Cabernet Mitos’) to 19.12 g/kg (‘Schwarzriesling’) of defatted dry matter (DM; ‘Schwarzriesling’) for integral grape seeds, whereas their content in the press residues ranged from 2.80 (‘Cabernet Mitos’) to 13.76 g/kg of defatted DM (‘Spätburgunder’). This is the first study presenting comprehensive data on the contents of individual phenolic compounds comprising all polyphenolic subclasses of press residues from grape seed oil production also covering the determination of the antioxidant activities of each subclass (Folin–Ciocalteu, FRAP and TEAC assays). Additionally, the effects of different solvents on the yields of phenolic compounds were determined. Maximum yields were obtained using methanol/0.1% HCl (v:v), water [75 °C] and a mixture of ethanol and water [3:1; v:v], respectively, whereas pure ethanol resulted in poor polyphenol extraction. The results of the present study confirm the press residues of grape seed oil production still to be a rich source of polyphenolics with strong antioxidant activity.     

Satiety in rats following blueberry extract consumption induced by appetite-suppressing mechanisms unrelated to in vitro or in vivo antioxidant capacity

Water extracts of two blueberry cultivars (‘Centurion’ and ‘Maru’) were tested for their ability to modify appetite in a rat model. The fruits of ‘Centurion’ had higher in vitro antioxidant capacity (as measured using the ferric reducing antioxidant power (FRAP) assay) and higher total phenolic content (TPC, as measured by the Folin–Ciocalteu method) than fruits of ‘Maru’. When rats were gavaged with water-soluble blueberry extract (BBE; 1 ml/day) of both cultivars for 6 days, serum FRAP increased significantly when compared to water-gavaged controls, indicating that BBE may have the ability to elevate circulating antioxidant potentials in vivo. Both cultivars had a satiating influence on experimental rats, as evidenced by their ability to decrease food intake by 8.6% (‘Maru’) and 6.2% (‘Centurion’), although a statistically significant decrease over the control rats was achieved only for the ‘Maru’ treatments. In addition, body weight gain of rats gavaged with extracts from ‘Maru’ and ‘Centurion’ cultivars decreased by 9.2% and 5.3% relative to the rats in the control group, respectively. The reduction in food intake over a 4 h period compared to a control treatment preloaded with the same volume of water suggests that the decrease in food intake was mainly a consequence of a satiating effect, rather than a stomach distension effect. The observed results suggest that the reduction in food intake and decrease in body weight in experimental animals is not merely a consequence of antioxidant mechanisms. BBE may provide a good satiety inducer and weight management modulator.     

Effects of storage temperature and duration on chemical properties,proximate composition and selected bioactive components of pomegranate (Punica granatum L.) arils

Effects of storage temperature on nutritional composition of pomegranate cultivars (‘Arakta’, ‘Bahgwa’ and ‘Ruby’) were investigated. Pomegranate arils were stored at 1, 4, and 8 °C at 95% relative humidity for 14 days. Arils stored at 1 °C were removed from storage after 14 days and kept at ambient conditions for one day. Anthocyanins, ascorbic acid and proximate composition were measured on day 0, 7, 14 and 15. O₂ consumption and CO₂ production increased at elevated temperatures. Proximate composition of pomegranate arils was similar amongst cvs.: 0.8 g/g moisture, 5.2 g kg⁻¹ ash, 13–15 g kg⁻¹ fat, 27–29 g kg⁻¹ dietary fibre, 11–12 g kg⁻¹ protein, 140–150 g kg⁻¹ carbohydrate and 310–320 kJ 100 g⁻¹ energy. ‘Arakta’ had highest titratable acidity (TA) level (0.3 ± 0.01 g 100 mL⁻¹) and ascorbic acid (26.0 ± 1.3 mg kg⁻¹). Low β-carotene levels (1.7–3.5 mg kg⁻¹) were detected in all samples. Nutritional composition of arils was not significantly affected at 1 and 4 °C for 14 d. Temperature did not affect total soluble solids (TSS), but increased TA and reduced TSS/TA. No mould growth was observed in arils stored at 1 °C after 14 d.     

Pressurised liquid extraction combining LC–DAD–ESI/MS analysis as an alternative method to extract three major flavones in Citrus reticulata ‘Chachi’ (Guangchenpi)

Pressurised liquid extraction (PLE) of three major flavones (hesperidin, nobiletin, and tangeretin) from the peels of Citrus reticulata ‘Chachi’ (Guangchenpi) was investigated. These flavones were quantified and analysed by liquid chromatography–diode array detector–electrospray ionisation mass spectrometry (LC–DAD–ESI/MS). The PLE procedure was optimised, validated and compared with other conventional extraction techniques. PLE gained the best result due to the highest extraction efficiency within the shortest extraction time. The optimal conditions of PLE were employing 70% methanol as extraction solvent at a temperature of 160 °C and extraction pressure of 1500 psi, using one extraction cycle with a static extraction time of 20 min. MS coupling with an ESI interface in the positive ion mode was used as the detection technique. This is the first report on combining PLE with LC–DAD–ESI/MS for the extraction and quantification of flavones in Citrus reticulata ‘Chachi’.     

Identification and quantification of major phenolic compounds from mango (Mangifera indica, cv. Ataulfo) fruit by HPLC–DAD–MS/MS-ESI and their individual contribution to the antioxidant activity during ripening

Mango (Mangifera indica L.) is an economically important fruit throughout the world. ‘Ataulfo’ mango, a leading cultivar in Mexico, has the highest content of phenolic compounds among several commercial varieties of mango. However, the individual identification and antioxidant contribution of these phenols during ripening of mango fruit is unknown. Qualitative and quantitative analysis of the major phenolic compounds found in ‘Ataulfo’ mango fruit pulp was conducted in four stages of ripeness, using high-performance liquid chromatography coupled to mass spectrometry. The antioxidant contribution of each of the major phenolic compounds was calculated. The major compounds identified were chlorogenic acid (28–301 mg/100 g DW), gallic acid (94.6–98.7 mg/100 g DW), vanillic acid (16.9–24.4 mg/100 g DW), and protocatechuic acid (0.48–1.1 mg/100 g DW). The antioxidant contribution of the four phenolic acids increased during ripening. Gallic acid accounted for the highest contribution (39% maximum value), followed by chlorogenic acid (21% maximum value). This could indicate that these phenolic compounds may have an important role in the antioxidant metabolism in ‘Ataulfo’ mango fruit during ripening, and promoting health benefits to consumers.     

Fatty acid composition and antioxidant system in relation to susceptibility of loquat fruit to chilling injury

Two cultivars of loquat fruit with contrasting chilling resistance were stored at 1 °C for 35 days to investigate the relationship between chilling injury and fatty acid composition and its antioxidant system. No symptoms of chilling injury occurred in the fruit of ‘Qingzhong’ cultivar during the whole storage, whereas in ‘Fuyang’ fruit, chilling injury increased sharply after 21 days of storage at 1 °C. ‘Qingzhong’ fruit had lower levels of superoxide radical and H₂O₂, in addition to lower lipoxygenase activity, but higher membrane lipid unsaturation and higher activities of superoxide dismutase and catalase than ‘Fuyang’. Furthermore, the chilling resistant ‘Qingzhong’ fruit also showed higher activities of antioxidant enzymes involved in ascorbate–glutathione cycle and higher levels of ascorbate acid and reduced glutathione. These results suggest that the higher membrane lipid unsaturation and the more efficient antioxidant system were both beneficial in enhancing resistance of loquat fruit to chilling injury.     

Miniature handheld NIR sensor for the on-site non-destructive assessment of post-harvest quality and refrigerated storage behavior in plums

This study evaluated the feasibility of using a handheld micro-electro-mechanical system (MEMS) spectrometer working in the 1600–2400 nm range for the measurement of quality-related parameters (soluble solid content, firmness, variety and post-harvest storage duration under refrigeration) in intact plums. Spectroscopic measurements were also made for each fruit using a diode-array Vis–NIR spectrophotometer (400–1700 nm) for purposes of comparison. A total of 264 plums (Prunus salicina L.) cv. ‘Black Diamond’, ‘Golden Globe’, ‘Golden Japan’, ‘Fortune’, ‘Friar’ and ‘Santa Rosa’, received and stored at 0 °C and 95% RH for 9 days, were used to build calibration models using different spectral signal pre-treatments and the modified partial least squares regression method. The two NIR instruments evaluated provided good precision, although the diode-array instrument yielded slightly greater precision for soluble solid content; statistic values were r² = 0.73 and the standard error of cross validation (SECV) = 1.11% for calibration, and r² = 0.68 and the standard error of prediction (SEP) = 1.22% for validation. Firmness measurements were less precise in both instruments, though again slightly better in the diode-array instrument: r² = 0.64 and SECV = 1.77 N for calibration; and r² = 0.61 and SEP = 2.30 N for validation, respectively. The performance of the two instruments for classifying plums by variety and by refrigerated post-harvest storage duration (0, 6 and 9 days) was evaluated using partial least square-discriminant analysis. A total of 96.5 % of samples were correctly assigned to their variety, while 94.5 % of plums were correctly assigned to their refrigerated storage day. In general, promising results were obtained with both instruments, with similar levels of accuracy for the measurements for soluble solid content, variety and refrigerated storage duration; the prediction model developed using the diode-array spectrophotometer provided better results for firmness.     

Physicochemical and microbiological characteristics of biltong,a traditional salted dried meat of South Africa

The microbiological and physicochemical characteristics of several commercial beef, kudu and springbok biltong samples from South Africa were assessed in this study. Analysis of samples allowed their differentiation into ‘dry’ and ‘moist’ samples. Dry biltong showed low moisture content (21.5–25.3 g/100 g), a low water activity (0.65–0.68) and a high salt content (5.5–7.9 g/100 g), while moist biltong showed a higher moisture content (35.1–42.8 g/100 g), a higher water activity (0.85 to 0.89) and a lower salt content (3.8–5.6 g/100 g). The pH value did not vary significantly between both groups (5.00–6.26). The results showed that dry biltong presented a low total plate count (TPC) content, a high level of lactic acid bacteria (LAB) and a high level of d-lactic acid as compared to moist biltong. These results suggest that dry biltong complies with the standard hygienic quality (TPC < 7 log cfu/g in agreement with the Food Standards Agency), while moist biltong samples generally showed a low content of d-lactic acid and a low ratio LAB/TPC.     

Comparative study of primary and secondary metabolites in 11 cultivars of persimmon fruit (Diospyros kaki L.)

Primary metabolites (sugars, organic acids) and secondary metabolites (phenolics and carotenoids) were quantified by HPLC in fully ripe fruit of 11 kaki cultivars: ‘Amankaki’, ‘Cal Fuyu’, ‘Fuji’, ‘Hana Fuyu’, ‘Jiro’, ‘O’Gosho’, ‘Tenjin O’Gosho’, ‘Thiene’, ‘Tipo’, ‘Tone Wase’ and ‘Triumph’. Amongst the analysed cultivars, ‘Tone Wase’ stands out as the richest in sugars, particularly glucose, and cultivars ‘Tipo’ and ‘Triumph’ contained the highest amounts of organic acids. Cultivars ‘O’Gosho’, ‘Cal Fuyu’ and ‘Hana Fuyu’ contained the least sugars and cultivar ‘Jiro’ the least organic acids. Amongst the individual phenolic compounds catechin and gallic acid were present in highest concentrations. The predominant carotenoid in both skin and pulp of ripe persimmon fruit was β-carotene, the highest content was measured in skin of cultivar ‘Hana Fuyu’, which also contained the highest level of total carotenoids. In persimmon pulp, much lower values for carotenoids were obtained, particularly in fruit of cultivar ‘Cal Fuyu’.     

Investigation of the retronasal flavour release during the consumption of coffee with additions of milk constituents by ‘Oral Breath Sampling’

The aim of this study was the investigation of the influence of milk proteins (casein and whey proteins) and milk fat on the release of flavour compounds from white coffee beverages in the oral cavity. For this reason a retronasal headspace technique for measurement of the after-flavour was adapted. A ‘Gas Sampler’ equipped with a mouthpiece was used as an ‘Oral Breath Sampler (OBS)’. Analyses were performed by gas chromatography with mass spectrometric detection. It was noticed that the sampling at different hours resulted in different standard deviations. The flavour release is more constant in the morning (Variation coefficient from 3% to 28%; median: 10%) than in the afternoon (7–52%; median: 23%). The relationships between flavour release and some salivary parameters like salivation rate, buffer capability and protein content were also studied. The ‘Oral Breath Sampling’ was considered to be a valuable sampling method for the analysis of the retronasal aroma release from coffee beverages.