Organic acids in two Portuguese chestnut (Castanea sativa Miller) varieties

The organic acids composition of two different chestnut (Castanea sativa Miller) varieties (Judia and Longal) were determined by HPLC/UV. In order to check the influence of the processing over these compounds, samples treated in three distinct manners (roasted, boiled and fried) were also analysed. The results showed that chestnut is characterized by the presence of seven organic acids: oxalic, cis-aconitic, citric, ascorbic, malic, quinic and fumaric acids. The organic acid quantitative profile allows the distinction of the two varieties. Longal variety samples presented higher organic acids contents than those from Judia variety. The contents of the pair malic plus quinic acids may be useful for the discrimination of the two varieties. Roasting, boiling and frying procedures lead to significant reduction of total organic acids contents.     

Metabolite composition of chestnut (Castanea sativa Mill.) upon cooking: Proximate analysis,fibre, organic acids and phenolics

The aim of this research was to study the processing effects (roasting and boiling) on primary and secondary metabolite composition of fruits from the following chestnut (Castanea sativa Mill.) cultivars (cvs.) of three Protected Designation of Origin (PDO) areas in the Trás-os-Montes e Alto Douro region (Portugal): PDO Terra Fria (cvs. Aveleira, Boaventura, Côta, Lamela and Trigueira), PDO Padrela (cvs. Judia, Lada, Longal and Negra) and PDO Soutos da Lapa (cvs. Longal and Martaínha). The cooking processes significantly (p < 0.0001) affected primary and secondary metabolite composition of the chestnuts. Roasted chestnuts had higher protein contents, insoluble and total dietary fibre and lower fat contents whilst boiled chestnuts had lower protein, but higher fat contents. Cooking increased citric acid contents, especially in roasted chestnuts. On the other hand, raw chestnuts had higher malic acid contents than cooked chestnuts. Moreover, roasted chestnuts had significantly higher gallic acid and total phenolics contents, and boiled chestnuts had higher gallic and ellagic acids contents, when compared to raw chestnuts. The present data confirms that cooked chestnuts are a good source of organic acids and phenolics and have low fat contents, properties that are associated with positive health benefits.     

Antioxidant activities of chestnut nut of Castanea sativa Mill. (cultivar ‘Judia’) as function of origin ecosystem

The antioxidant properties of different ecotypes of chestnut nut (cv. Judia) were studied. Total phenolics and flavonoids were also determinated. Total phenolics amount ranged from 9.6 mg/g of GAE (hottest ecotype, Murça) to 19.4 mg/g of GAE (coldest ecotype, Valpaços). Gallic and ellagic acid were the predominant compounds and Valpaços had the highest values while, Murça had the lowest ones. The antioxidant capacity of ethanolic extracts were evaluated through several biochemical essays: ABTS (2,2′-azinobis-(3-ethylbenzothiazoline-6-sulphonic acid)) and DPPH (2,2-diphenyl-1-picrylhydrazyl) radical-scavenging activity, FRAP (ferric reducing/antioxidant power) and inhibition of oxidative haemolysis in erythrocytes. In order to evaluate the antioxidant efficiency of each ecotype, the EC₅₀ values were calculated. Once again Valpaços revealed the best antioxidant properties, presenting much lower EC₅₀ values. Climatic conditions influence seems to be a limiting factor for production of phenolic compounds and consequently for the antioxidant properties of chestnut nuts.     

Nutritional quality of important food legumes

The proximate composition, mineral constituents and amino acid profile of four important legumes (chickpea, lentil, cowpea and green pea) were studied in order to evaluate their nutritional performance. Significant (P < 0.05) variations existed among the legumes with respect to their proximate composition, mineral constituent and amino acid profile. Lentil was found to be a good source of protein, while cowpea was good in ash among the grain legumes tested. All four types of legumes were also better suppliers of mineral matter, particularly potassium, phosphorus, calcium, copper, iron, and zinc. However, the concentrations of various mineral constituents was not in good nutritional balance. It was concluded that the four legumes tested were rich in lysine, leucine and arginine and can fulfil the essential amino acid requirement of human diet except for S-containing amino acids and tryptophan. In order to make good, the deficiency of certain essential amino acids in legume protein, they must be supplemented with other vegetables, meat and dairy products (e.g., Whey, yogurt).     

Aromatic potential of Castanea sativa Mill. compared to Quercus species to be used in cooperage

The composition of volatile and semi-volatile compounds of chestnut (Castanea sativa Mill.) was studied and compared to oak wood species frequently used in cooperage (Quercus alba, Quercus petraea, Quercus robur and Quercus pyrenaica) to evaluate its aromatic potential. Chestnut was found to be a suitable wood for use in ageing processes, based on the large, diverse number of detected compounds (e.g., lactones, furanic compounds, terpenes, lignin derivatives and triterpenic compounds). Chestnut wood possessed high levels of volatile phenols and phenolic aldehydes, specifically vanillin and its derivatives. Each wood species exhibited a characteristic, quantifiable composition of volatile compounds, and therefore, the sensorial profile of each wood species is expected to be different. The levels of certain volatile compounds were also useful for discriminating among the studied wood species.     

Characterization,amino acid composition and in vitro digestibility of hemp (Cannabis sativa L.) proteins

The protein constituents and thermal properties of hemp (Cannabis sativa L.) protein isolate (HPI) as well as 11S- and 7S-rich HPIs (HPI-11S and HPI-7S) were characterized by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and different scanning calorimetry (DSC), and their amino acid composition and in vitro digestibility were also evaluated, as compared to soy protein isolate (SPI). SDS-PAGE analysis showed that the edestin (consisting of acidic and basic subunits, AS and BS) was the main protein component for HPI and HPI-11S, while HPI-7S was composed of the BS of edestin and a subunit of about 4.8 kDa. DSC analysis characterized thermal transition of the edestin component and the possible present form of different subunits. Except lysine and sulfur-containing amino acids, the essential amino acids of various HPIs met the suggested requirements of FAO/WHO for 2–5 year old infants. The proportion of essential amino acids to the total amino acids (E/T) for HPI (as well as HPI-11S) was significantly higher than that of SPI. In an in vitro digestion model, various protein constituents of various HPIs were much easily digested by pepsin plus trypsin, to release oligo-peptides with molecular weight less than 10.0 kDa (under reduced condition). Only after pepsin digestion, in vitro digestibility of HPIs was comparable to that of SPI, however after pepsin plus trypsin digestion, the digestibility (88–91%) was significantly higher than that (71%) of SPI (P < 0.05). These results suggest that the protein isolates from hempseed are much more nutritional in amino acid nutrition and easily digestible than SPI, and can be utilized as a good source of protein nutrition for human consumption.     

Nutritional composition of the kernels from Canarium album L.

The kernels from Canarium album L. (also called Chinese olive), largely cultivated in the southeast of China, were analyzed for their nutritional composition. The kernels had a high percentage of fats (52.8%) and proteins (29.5%). Soxhlet extracted kernel oil presented acid, iodine and saponification values of 0.56, 84.6 and 192, respectively. Gas chromatography–mass spectroscopy (GC–MS) analysis of kernel oil revealed that oleic acid (30.5%) and linoleic acid (41.8%) were the major unsaturated fatty acids, while palmitic acid (18.0%), stearic acid (7.83%) and arachidic acid (0.39%) were the main saturated ones. Potassium, calcium and magnesium were the predominant mineral elements present in the kernels. Sodium, iron, manganese and zinc were also detected in appreciable amounts. The kernel proteins were rich in arginine, glutamic and aspartic acids (3.19%, 5.02% and 2.47%, respectively) while the limiting amino acids were methionine and lysine.     

Characterization of polyphenol oxidase from butter lettuce (Lactuca sativa var. capitata L.)

Polyphenol oxidase (PPO) was isolated from butter lettuce (Lactuca sativa var. capitata L.) grown in Poland and its biochemical characteristic were studied. PPO from butter lettuce showed a higher affinity to 4-methylcatechol than to catechol. The K_M and V_max values were: 3.20 ± 0.01 mM and 4081 ± 8 U/ml min⁻¹ for catechol and 1.00 ± 0.09 mM and 5405 ± 3 U/ml min⁻¹ for 4-methylcatechol. The optimum pHs of the enzyme were found to be 5.5 using catechol and 6.8 using 4-methylcatechol as substrate. The enzyme had a temperature optimum of 35 °C. The enzyme was relatively stable at 30 °C and 40 °C. The times required for 50% inactivation of activity at 50 °C, 60 °C and 70 °C were found to be about 30, 20 and 5 min, respectively. Inhibitors used for investigation in this study were placed in relative order of inhibition: p-hydroxybenzoic acid > glutathione ≈ ascorbic acid > l-cysteine > EDTA > citric acid. The enzyme eluted in the chromatographic separations was analyzed electrophoretically under denaturating conditions. The analysis revealed a single band on the SDS–PAGE which corresponded to a molecular weight of 60 kDa.     

Nutritional characteristics of seed proteins in 15 Lathyrus species (fabaceae) from Southern Spain

The nutritional characteristics of seed proteins of 15 Spanish Lathyrus species have been analyzed. Protein contents in studied Lathyrus ranged from 17.7% in Lathyrus sativus to 25.6% in L. tingitanus with a 22.4% average protein content in studied Lathyrus. Among essential amino acids the most abundant were Leu, Lys, Phe, Thr and Val. Also, all species contained Lys above FAO recommendations. On the contrary, all species were limiting in Trp ranging from 0.5% to 0.8% content and were also limiting in sulphur containing amino acids, Met and Cys. In vitro protein digestibility (IVPD) in studied Lathyrus ranged from 76.0% in L. pratensis to 86.5% in L. annuus, with an average IVPD of 80.5%. Nutritional parameters, such as protein efficiency ratio, corresponded to high quality proteins. Protein digestibility corrected amino acid score was similar to the observed in other legumes such as lentil or peanut. An analysis of similarity based on the profile of seed protein amino acid composition showed, in the cluster generated, correlation with the taxonomic classification of these species according to morphological characters. Results confirm the interest of studying wild populations of cultivated and non-cultivated Lathyrus species as source of seeds with good nutritional characteristics.     

Nutritional quality and safety of cooked edible crab (Cancer pagurus)

Edible crab (Cancer pagurus) is one of the most important crustaceans consumed in Southern European countries, either as boiled or steamed cooked product. So far, the majority of studies assessing health benefits and risks associated to seafood consumption have been carried out in raw products, despite being generally cooked before consumption, and mostly in muscle tissue. Therefore, the aim of this study was to assess the effect of steaming and boiling on the chemical safety and nutritional value of C. pagurus caught in spring and summer. Generally, chemical and elemental composition of brown meat (tissue in the body cavity comprising mainly gonads and hepatopancreas) differed significantly from muscle (white meat in claws and legs). Additionally, the same tissue revealed differences in chemical and elemental composition of raw and cooked C. pagurus, likely due to water leaching. In contrast, few variations between seasons were observed. The results revealed that the consumption of cooked edible crab muscle should be promoted, whereas brown meat ingestion should be done parsimoniously.     

Isolation and characterisation of the sesquiterpene lactones from Lactuca sativa L var. anagustata

Lactuca sativa L var. anagustata is widely used as both a delicious vegetable and a traditional medicine in China. Chemical investigation of the methanolic extract of L. sativa L var. anagustata has now led to the isolation of three new sesquiterpenes, together with eight known ones. All the compounds were isolated by chromatography on a silica gel column and preparative thin-layer chromatography (PTLC). Their structures were elucidated by means of spectroscopic methods, including 2D-NMR experiments. Cytotoxicity of the new compounds was assayed against selected cancer cell lines, including the human epithelial carcinoma (HeLa) and human colon carcinoma (HCT-116) cell lines. Radical-scavenging activities of the seven compounds were determined by DPPH radical-scavenging assay.     

Nutritional properties of yellow mombin (Spondias mombin L.) pulp

Yellow mombin (Spondias mombin L.) is a tropical fruit with increasing acceptance in both national and international fruit markets. The aim of this work was to evaluate the centesimal composition, mineral content, total phenolics, antioxidant activity, and characterize the carotenoids of frozen yellow mombin pulp. Results indicated that the yellow mombin pulp contained an important amount of potassium and copper. The antioxidant activity and total phenolic values scored 17.5 mmol TEAC g⁻¹ and 260 mg galic acid/100 g respectively, higher than those reported for other fruits. Five carotenoids were identified, ??-cryptoxanthin, lutein, zeinoxanthin, ?? and ?? carotene, being ??-cryptoxanthin the major one, accounting for the high level of pro-vitamin A activity in the pulp. A 100 g portion of yellow mombin pulp can provide more than 37% of the recommended daily allowance of vitamin A.     

Nutritive value of masau (Ziziphus mauritiana) fruits from Zambezi Valley in Zimbabwe

Ziziphus mauritiana (masau) fruits are consumed by many people in Zimbabwe. The fruits contribute significantly to people’s diet when they are in season. The objective of this study was to determine the nutritional content of the fruits and, hence, quantify their contribution to the diet. Samples of masau were collected in two seasons (August 2006 and August 2007). Both macronutrients and micronutrients were determined using standard AOAC methods of analysis. Dry matter content ranged from 21.1 ± 0.2 to 24.1 ± 0.3 g 100 g⁻¹ of edible portion of the sweet and sour fruits, and 84.8 ± 0.2 to 87.2 ± 0.2 g 100 g⁻¹ for the dried fruit. Crude protein per 100 g edible portion of dry weight ranged between 7.9 ± 0.0 and 8.7 ± 0.0 g, crude fat from 0.8 ± 0.0 to 1.5 ± 0.0 g, crude fibre from 4.9 ± 0.0 to 7.3 ± 0.0 g, ash between 3.0 ± 0.0 and 4.3 ± 0.0 g and carbohydrate between 79.5 ± 0.0 and 83.2 ± 0.0 g. The fruits were rich in vitamin C (15.0 ± 0.0–43.8 ± 0.02 mg 100 g⁻¹) and the energy values ranged between 1516.0 ± 1.73 and 1575.0 ± 2.3 kJ 100 g⁻¹. Furthermore, the fruits contained (mg 100 g⁻¹ of dry weight) potassium from 1865.0 ± 1.3 to 2441.0 ± 1.1, calcium from 160.0 ± 0.3 to 254.0 ± 0.1, sodium between 185.0 ± 0.1 and 223.0 ± 0.2, magnesium between 83.0 ± 0.0 and 150.0 ± 0.13 and phosphorous from 87.0 ± 0.1 to 148.0 ± 0.5. Manganese and copper contents ranged between 0.7 ± 0.03 and 1.6 ± 0.03, while iron and zinc ranged between 2.1 ± 0.43 and 4.3 ± 0.1, and 0.6 ± 0.0–0.9 ± 0.0 mg 100 g⁻¹ of dry weight, respectively. The masau fruit is therefore a good potential source of carbohydrates, proteins and micronutrients, such as calcium, potassium, sodium, phosphorous, copper, iron, Vitamin C and zinc.     

Comparison of wild and cultured sea bass (Dicentrarchus labrax) quality

Chemical composition, nutritional value and other physico-chemical parameters of sea bass from two different geographical areas (Greece and Spain) and from aquaculture and wild origin were studied. Farmed and wild fish differ in proximate composition, colour, and especially in texture, fatty acids and free amino acids (FAAs) profiles. Flesh of wild fish was firmer, which could be attributed to their lower fat content and higher level of activity. Cultured fish showed a higher content of monounsaturated fatty acids and lower of saturated and polyunsaturated fatty acids (PUFAs). Within the PUFA group, n−3 fatty acids were predominant in wild sea bass, while n−6 were more abundant in farmed fish. Some FAAs related to the characteristic flavour of fish, such as glutamic acid, aspartic acid, alanine, and glycine were more abundant in cultured sea bass. No differences between fish from both farms were found, due to the similar composition of the feed used.     

Nutritional composition of underutilized bayberry (Myrica rubra Sieb. et Zucc.) kernels

The kernels of five bayberry cultivars (Biqi, Zaodamei, Ding-ao, Dongkui and Wandao), grown in Zhejiang Province, China, were analyzed for their proximate composition, protein fractionation, amino acid profile, fatty acid composition and mineral contents. The antinutritive compounds, tannin and cyanide, were also quantified. These bayberry kernels possessed 25.0–27.64% DW protein. A majority of storage protein in bayberry kernels was of the globulin form. The kernel protein was rich in methionine, arginine, aspartic and glutamic acids while limiting amino acid was lysine. The most outstanding feature was the abundant fat content (62.5–68.1% DW) of kernels. Approximately 84.9–90.1% of the fatty acids were unsaturated with oleic acid (43.3–50.7%) and linoleic acid (34.1–46.8%). Bayberry kernels were good sources of magnesium, potassium and calcium. These results may offer a scientific basis for use of the under-exploited bayberry seeds.     

Susceptibility of commercial oat cultivars to Cryptolestes pusillus and Oryzaephilus surinamensis

Susceptibility to two storage insect pests [(Cryptolestes pusillus (Schönherr) and Oryzaephilus surinamensis (L.)] of eight commercial oat cultivars from the United States was determined in laboratory studies. Duration of insect development was shorter and number of progeny produced was greater on cracked than on whole oats. Simulations based on data from the study showed that insect populations would reach the threshold level for treatment in 2-3 months of storage at 30°C on cracked oats. Insect population development was slowest on the hulless cultivar Paul when the oat kernels were cracked. Simulations also indicated that all cultivars of whole oats tested could be stored for at least 1 yr at 30°C without reaching the threshold for treatment when infested with these two species of insects, and insect populations would decrease over time on the cultivars Don, Jerry, Milton, NewDak, Otana, and Valley. Analyses of oat grain quality characteristics, including kernel weight, groat hardness, and groat composition, provided little insight into the mechanism of observed differences in insect development among cultivars. Hardness of the kernels (as indicated by % broken groats after dehulling) may be related to near immunity to these two species of insects in whole Otana. Steaming whole oats to inactivate hydrolytic enzymes in the trichomes of the pericarp did not increase susceptibility to these two species of insects, suggesting that enzymes in the trichomes were not responsible for insect population development being slower on whole oats than on cracked oats. Although we were unable to identify the factors that determined relative susceptibility in this study, the results will be useful for selecting commercial oat cultivars for planting that will be less susceptible to insect pests in storage and suggest that the economics of cleaning oats before storage to reduce insect population growth should be investigated.     

Comparison of physico-chemical parameters and composition of mussels (Mytilus galloprovincialis Lmk.) from different Spanish origins

In this study, different physico-chemical analyses were carried out on mussels cultured at three different Spanish areas: Ría de Vigo (Galicia), the Ebro Delta (Catalonia) and Valencia Harbour (Valencian Community), in order to evaluate the influence of origin on the biometric parameters, chemical composition, and water holding capacity. Mussels from the three sites showed different proximate composition. Molluscs from Valencia showed the smallest size and the highest meat yield. All samples exhibited low concentrations of Cu and Mn, and high contents of Na, K, Ca, Mg, and P. The highest level of total free amino acids (FAA) was found in mussels from the Ebro Delta and the lowest in those from Valencia. Taurine was the main FAA in all mussels. Saturated fatty acids predominated over monounsaturated and polyunsaturated ones. Contents of palmitic acid were the highest in all samples. Galician mussels exhibited the highest amount of eicosapentaenoic acid and the lowest of docosahexaenoic acid. Mussels from the three sites showed a characteristic volatile fraction which conferred a typical flavour depending on their origin.     

Characterization of various chestnut cultivars by means of chemometrics approach

Chestnuts like other foodstuffs may be characterized by their chemical composition. The chemical composition of ascorbic acid, total acidity, pH, starch, refraction index (°Brix), moisture, ashes, insoluble fibre, soluble fibre, total dietary fibre, total proteins, cations (Na, K, Ca, Fe, Cu, Zn, Mn, Mg) and phosphorous was determined in 19 local chestnut varieties from three areas of production in the island of Tenerife. Significant differences were found between the mean values of moisture, starch, total phenols contents, total soluble and non-soluble fibre, Ca, Cu, K, Mg and Zn, obtained according to the area of production. Distribution patterns of the samples were established for correlating the chemical composition of the chestnuts and varieties, using different chemometrics tools such as cluster analysis, principal component analysis, factor analysis and linear discriminant analysis (LDA). Initially, cluster analysis made it possible to establish a primary relationship between the variables. When applying stepwise LDA the chestnut samples were well classified within their area of production. Also, when the stepwise LDA was used on the chestnut samples from area of production 2, 100% of the chestnut samples were also correctly classified within their variety.