Estimation of the degree of polymerization of condensed tannins of some wild fruits of Zimbabwe (Uapaca kirkiana and Ziziphus mauritiana) using the modified vanillin‐HCl method

Methanol and glacial acetic acid were compared for their effect in the vanillin assay for tannins. The time taken for the development of colour was followed using a spectrophotometer. By reacting vanillin and condensed tannins in the presence of acetic acid, the time for the development of the chromogenic substance was reduced approximately threefold compared with the time taken in the presence of methanol. The degree of polymerization was followed by reacting a catechin standard, the tannin of the Uapaca kirkiana and Ziziphus mauritiana, with vanillin in acetic acid medium at 30 °C and measuring absorbance at intervals. The values obtained suggested between 4 and 10 monomer units of catechin per polymer of tannins for the different portions of the two fruits. Copyright © 2005 Society of Chemical Industry     

Exploiting locally available resources for food and nutritional security enhancement: wild fruits diversity, potential and state of exploitation in the Amhara region of Ethiopia

This paper features the composition of wild fruits, their exploitation and their potential contribution to improved food and nutritional security in three districts of the Amhara region of Ethiopia. Data were gathered through structured, semi-structured and key-informant interviews which were administered to the heads of 92 randomly chosen households. Focus group discussions and direct field explorations by the researchers were also undertaken. The results revealed that altogether 44 wild fruit species are available for use in the study areas. The fruits are rich in valuable nutrients and are accessible year-round with significant overlap at times of acute food and nutrient scarcity. Nevertheless, owing to the peoples’ cereal-based dietary habits, cultural perceptions and attitudes, the current state of fruit utilization is very low. Consequently, the potential nutritional contribution of wild fruits to the people’s diets remains largely unexploited. In order to remedy this situation, a wider and sustained acceptance of wild fruits as important dietary components must be fostered.

Extraction optimization of bioactive compounds (crocin, geniposide and total phenolic compounds) from Gardenia (Gardenia jasminoides Ellis) fruits with response surface methodology

Response surface methodology (RSM) was employed to optimize the extraction parameters of crocin, geniposide and total phenolic compounds from gardenia fruits. The effects of three independent variables, namely ethanol concentration (EtOH, %), extraction temperature (°C) and time (min) on the yield of crocin, geniposide and total phenolic compounds were investigated. Results indicated that the data were adequately fitted into three second-order polynomial models. The independent variables, the linearity of extraction temperature and time, the quadratics of ethanol concentration and extraction time, the interactions between ethanol concentration and temperature, ethanol concentration and extraction time, as well as extraction temperature and time had a significant effect on the yield of crocin, geniposide or total phenolic compounds. The optimal extraction parameters were the EtOH of 51.3%, extraction temperature of 70.4 °C and time of 28.6 min according to the response surface analysis. Under this condition, the yield of crocin, geniposide and total phenolic compounds was 8.41 mg/g, 109.0 mg/g and 24.97 mg CAE/g dry powder of gardenia fruits, respectively.

Industrial relevance

There is a strong interest in the food industry in studying the extraction optimization of natural plants to produce higher quality products. Response surface methodology (RSM) is an effective technique for analyzing interactions among factors and optimizing the processes or products where multiple variables may influence the outputs. This work explores the extraction conditions for a natural pigment-gardenia yellow pigment by the RSM method and optimizes the extraction parameters to improve extraction yields of same main components of the natural pigment at the same time. The mathematical methods and models which can describe and predicate experimental data of the extraction would be extremely helpful in the extraction process of the natural products.     

Purification and characterisation of multiple forms of polygalacturonase from mango (Mangifera indica cv. Dashehari) fruit

Three multiple forms of polygalacturonase (PG) namely PGI, PGII and PGIII were isolated, purified and characterized from ripe mango (Mangifera indica cv. Dashehari) fruit. Native molecular weights of PGI, PGII and PGIII were found to be 120, 105 and 65 kDa, respectively. On SDS–PAGE analysis, PGI was found to be a homodimer of subunit size 60 kDa each while those of PGII and PGIII were found to be heterodimers of 70, 35 and 38, 27 kDa subunit size each, respectively. Three isoforms of PG differed with respect to the effect of pH, metals, reducing agents and their susceptibility towards heat. PG isoforms also differed with respect to the effect of substrate concentration on enzyme activity. PGI and PGIII exhibited inhibition at high substrate concentration while PGII did not. Km for polygalacturonic acid was found to be 0.02% for PGI.     

Purification and characterisation of a soluble nucleotide pyrophosphatase/phosphodiesterase from prickly pear (Opuntia ficus indica) fruits

A glycosylated metallo-protein, nucleotide pyrophosphatase/phosphodiesterase, in a soluble form was purified to homogeneity from prickly pear (Opuntia ficus indica) fruits. The native protein had a molecular mass of 105 ± 8 kDa and was formed by two apparently identical subunits each containing 1 Ca²⁺ and 1 Mg²⁺ ion. The Opuntia enzyme exhibited hydrolytic activities toward pyrophosphate/phosphodiester bonds of a broad range of natural substrates, but among these, only NAD(P) and NAD(P)H were hydrolysed very efficiently. Moreover, Opuntia pyrophosphatase/phosphodiesterase hydrolysed the artificial substrate thymidine 5′-monophosphate 4-nitrophenyl ester, whereas it did not show any catalytic activity toward bis-4-nitrophenyl phosphate, which is a substrate of other pyrophosphatase/phosphodiesterase enzymes. We observed an increase of enzyme activity from the green to the red stage of fruits development, suggesting that ONPP activity might be related to the ripening of prickly pears. The protein was shown to be resistant to 75 °C for 30 min. Other biochemical characteristics were investigated and are reported here.     

Biochemical,sensory and microbiological attributes of wild turbot (Scophthalmus maximus), from the Black Sea,during chilled storage

Freshness of wild turbot (Scophtalmus maximus) stored in ice was assessed by chemical, sensory and microbiological methods. The limit for sensory acceptability of wild turbot stored in ice was ∼12–15 days. The quality of turbot decreased on day 15 (B) and they were no longer acceptable on day 19 (C). The TVB-N level showed fluctuations during storage, indicating that TVB-N could not be a good indicator of turbot quality. The release of FFA increased from an initial value of 6.33 (expressed as % of oleic acid) to a final value of 20.6 during the storage period. The initial PV value was 5.60 meq/kg for turbot stored in ice and it started to increase to 21.6 meq/kg on day 12 and then started to decrease to 13.6 meq/kg at the end of storage period. The level of TMA in wild turbot increased sharply from an initial value of 9.36 mg/kg to a final value of 38.9 mg/kg. Linear regressions (r²) obtained from K, K_i, G, P, H and F_r were 0.92, 0.89, 0.99, 0.89, 0.96 and 0.89, respectively, for the wild turbot stored in ice. Turbot maintained high (E) and good quality (A) during the first 12 days of chilled storage when the average K, K_i and P values were ∼78–85%, and H, F_r and G values were ∼45%, 15% and 149%, respectively. Eight biogenic amines were investigated, namely, histamine, putrescine, cadaverine, spermidine, spermine, tryptamine, tyramine, and 2-phenylethylamine, three amines (histamine, tyramine, and tryptamine) were not detected in any of the fish samples during the storage period. As storage time progressed, putrescine and cadaverine became the dominant amines, reaching 22.7, and 16.9 mg/kg, respectively, at 19 days of storage in ice. Total viable counts of whole gutted turbot increased from the initial value of 3.3 log cfu g⁻¹ (day 0) to 7.87 log cfu g⁻¹ (day 19) over the period of storage. If 10⁶ microorganisms/g are considered to be the TVC limit of acceptability, the shelf life of turbot was approximately ∼13–14 days.     

罗望子胶与常用胶体的复配研究

为探究K⁺对罗望子胶/κ-卡拉胶复合凝胶的特性及机理的影响,本文采用流变学、质构分析、微观结构和红外光谱四种方法,对不同K⁺添加量的复合凝胶的性能和结构进行研究。流变学结果显示,K⁺的添加使凝胶体系的模量升高,柔量和总形变量降低,K⁺添加量增至15 mmol/L时,表观粘度达到最高值2690 Pa·s;质构分析结果显示随K⁺添加量的增大,凝胶体系强度和硬度增大,但弹性和内聚性相对减少;而红外光谱和微观结构证明了K⁺可以促进两种凝胶体系之间的相互作用,使凝胶孔隙趋于致密均匀,在K⁺添加量15 mmol/L时孔径间壁最为规则结实。结果表明,K⁺的添加能够使凝胶体系表现较好的粘弹性和抗变形性,使网状结构更加紧密,为罗望子胶和κ-卡拉胶的复配应用提供了理论参考。     

西洋参多糖PPQI-1~4的分离和表征

通过酶法水解西洋参多糖（American ginseng polysaccharides,AGP）制得西洋参低聚糖（American ginseng oligosaccharides,AGOS）,测定AGP和AGOS的ABTS⁺、DPPH、OH、O₂^-自由基清除率、Fe²⁺螯合能力和总还原力,α-葡萄糖苷酶和α-淀粉酶抑制能力,胆固醇结合能力、胆酸钠结合能力和脂肪酶抑制能力等,研究了AGP和AGOS的抗氧化活性、体外降血糖能力和体外降血脂能力。结果表明,纤维素酶酶解西洋参多糖的最佳条件为：反应温度45 ℃、底物浓度20 mg/mL、加酶量100 U/mg、酶解时间90 min,此条件下AGP酶解产物平均聚合度为2.74。西洋参低聚糖对ABTS⁺、DPPH和OH自由基具有更好的清除能力,其清除率分别达到了74.63%、79.98%和99.94%;对α-葡萄糖苷酶、α-淀粉酶和脂肪酶具有更好的抑制能力,其抑制率分别达到了35.76%、62.45%和98.55%。研究结果表明西洋参低聚糖较西洋参多糖具有更强的体外功能活性,可以作为具有潜力的功能性食品被进一步开发利用。     

The suitability of dried fruits, almonds and carobs for the development of Ephestia figulilella Gregson, E. calidella (Guenee) and E. cautella (Walker) (Lepidoptera: Phycitidae)

In experiments at 30°C, 70% r.h. and a light régime of 16 hr light/8 hr dark 30 freshly-hatched larvae were placed singly on ripe carob pods obtained direct from Cyprus, and almonds, dates and raisins bought from a shop. The raisins had been treated commercially with paraffin oil prior to export. All 3 species thrived on ground carobs and dates. Between 17 and 26 individuals of each of these species completed development and emerged as adults on these foods. The particle size of carobs had a considerable influence, for only 13 E. calidella and 8 of each of E. figulilella and E. cautella completed development on carob pieces. Only 1 adult of E. calidella was bred from almonds, and 2 from raisins; 9 adults of E. figulilella were bred from almonds, and 16 from raisins, whilst E. cautella gave 17 adults on almonds and 3 adults on raisins.

The shortest mean developmental period for E. figulilella was 34 days on ground carobs, for E. calidella it was 37 days on carob pieces and for E. cautella 35 days on almonds. The longest mean developmental periods were 56 days for E. figulilella and 59 days for E. calidella, both on almonds, and 84 days for E. cautella on raisins.

The significance of these laboratory results in relation to field and warehouse observations is discussed.     

High resolution two-dimensional electrophoresis as a tool to differentiate wild from farmed cod (Gadus morhua) and to assess the protein composition of klipfish

Tris and CHAPS–urea extracts from wild and farmed cod muscle and from rehydrated cod klipfish fillets were analyzed by one (1DE) and two-dimensional electrophoresis (2DE). 2DE maps of tris extracts from farmed cod differed from the wild in a series of spots of Mw 35 and 45 kDa. The CHAPS–urea extracts from farmed cod had a several spots of Mw between 100 and 45 kDa, which were hardly detectable in wild cod and very prominent in klipfish. Klipfish was clearly different from the other samples: the myosin heavy chain was hardly detectable in these samples, and the tris extracts contained fewer, and the CHAPS–urea more spots than the corresponding extracts from the raw muscles. Further identification of these potentially diagnostic spots will make it easier the differentiation of farmed from wild cod and the evaluation of klipfish processing on the protein content of the product.     

Comparative analysis of total phenolic content, antioxidant activity, and flavonoids profile of fruits from two varieties of Brazilian cherry (Eugenia uniflora L.) throughout the fruit developmental stages

A better characterization of the flavonoids profile and antioxidant activity of Brazilian cherry fruits is expected to significantly increase their marketing appeal. Fruits at the green stage presented the highest antioxidant activity, measured as DPPH scavenging activity (17.18 and 18.13 mmol Trolox equivalents/100 g dried fruits for the red and purple varieties, respectively), and total phenolic content (4.14 and 5.81 g of ferulic acid equivalents/100 g dried fruit for the red and purple varieties, respectively), as well. Use of tandem mass spectrometry allowed the identification of myricetin 3-O-hexoside, myricetin 3-O-pentoside, myricetin 3-O-rhamnoside, quercetin 3-O-hexoside, quercetin 3-O-pentoside, quercetin 3-O-rhamnoside, and myricetin deoxyhexoside-gallate in both varieties of Brazilian cherry, regardless the developmental stage. Our data indicate that Brazilian cherry fruits are rich in natural antioxidants that might be more widely used by both, the general population and the food industry as a source of bioactive human health promoter phytochemicals.     

Proteolysis,physicochemical characteristics and free fatty acid composition of dry sausages made with deer (Cervus elaphus) or wild boar (Sus scrofa) meat: A preliminary study

In order to contribute to typifying delicatessen made with game meat, the proteolysis, physicochemical characteristic and free fatty acid composition were determined in 10 commercial dry sausages, chorizos and saucissons, made with deer or wild boar meat. The a_w and pH values were similar for all the samples; however, the results for dry matter, protein nitrogen, fat, ash, sodium chloride, phosphorus, and sodium nitrite content showed great variation among the samples tested. The myofibrillar protein content was higher than the sarcoplasmic protein content in all samples analysed. The electrophoretic profiles of sarcoplasmic and myofibrillar proteins were different among samples. Principal components analysis, run on the relative density of myofibrillar and sarcoplasmic proteins, separated the chorizo and saucisson samples. Chorizo samples were a homogeneous group in the analysis of myofibrillar proteins, which indicated similar proteolysis effects for all samples. The majority acids were oleic, palmitic, linoleic and stearic in all samples. Chorizos differed from saucissons in the greater quantity (P < 0.05) of polyunsaturated fatty acids.     

Carcass and meat quality traits of wild boar (Sus scrofa s. L.) with 2n = 36 karyotype compared to those of phenotypically similar crossbreeds (2n = 37 and 2n = 38) raised under the same farming conditions 2: Fatty acid profile and cholesterol

The aim of this study was to compare European wild boar (Sus scrofa) with chromosomal number 2n = 36 to phenotypically similar animals with 2n = 37 and 2n = 38 chromosomes (crossbreeds) with respect to fatty acid (FA) profile and cholesterol content. According to gender and genetic group (2n = 36, 2n = 37, and 2n = 38; seven animals each), the FA profile in longissimus dorsi (LD), semimembranosus (SM) muscles, and back fat was measured. Cholesterol content of LD and SM muscles was also analysed. The animals were fed and reared under the same conditions until slaughter at the age of nine months. FA profiles of LD, SM, and back fat were measured by GC and cholesterol with HPTLC. SM muscle of wild boar group (2n = 36) showed a higher proportion of PUFAs and lower C16:0 and C18:0 than that of crossbreeds. No differences in the FA profiles of LD and cholesterol content of LD and SM muscles among karyotypes were found.     

Sensory, microbiological, physical and chemical properties of cuttlefish (Sepia officinalis) and broadtail shortfin squid (Illex coindetii) stored in ice

The objective of this study was to characterize whole raw cuttlefish (Sepia officinalis) and shortfin squid (Illex coindetii) during storage in ice through sensory, microbiological, chemical and physical analyses. The recently developed Quality Index Method (QIM) tables for these species were used for sensory analysis. Shelf-life of whole cuttlefish and shortfin squid were estimated as around 10 and 9 days, respectively, according to QIM, which is shorter than for most species, especially fish. The numbers of microorganisms found in cuttlefish and shortfin squid surfaces until rejection were lower than in fish, which suggest predominance of enzymatic (autolytic) degradation. H₂S-producing bacteria constituted a significant proportion of the spoilage flora. Physical analysis performed using the RT-Freshmeter and the Torrymeter showed these instruments can be applied to cuttlefish and shortfin squid, providing useful complementary information on the rates of change of electrical properties. Free tryptophan and VBN contents significantly changed during the first storage week indicating that low levels of these compounds could be used as indicators of fresh and high quality cuttlefish and broadtail shortfin squid. Urea can be useful as spoilage indicator for cuttlefish, as well as agmatine for broadtail shortfin squid. An overall look into data obtained shows, as expected, that spoilage of these cephalopod species can be considered a different phenomena when compared to fish and is not yet completely clarified.     

Characterization of the phytochemicals and antioxidant properties of extracts from Teaw (Cratoxylum formosum Dyer)

The leaves of the Thai vegetable, Teaw (Cratoxylum formosum Dyer) were extracted with ethanol to provide an extract that had antioxidant properties. The composition of the extract was studied by high-performance liquid chromatography with a diode array detector, and by electrospray ionization mass spectrometry. The main antioxidant component (peak 1) was chlorogenic acid, which was present at 60% of the extract. Three minor components were present at 7%, 3% and 2%, and other components that were present at lower concentrations were also observed. Treatment of the Teaw extract with 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) caused a similar reduction in peak area of 55.2–58.1% for chlorogenic acid and the three minor components, indicating that these components had common structural features. Component 2 was identified as dicaffeoylquinic acid, and compounds 3 and 4 were identified as ferulic acid derivatives. The radical-scavenging activity of the Teaw extract was compared with -tocopherol, BHT and chlorogenic acid, using the DPPH and 2,2′-azinobis (3-ethylbenzothialozinesulfonic acid) radical cation (ABTS⁺) assays. The Teaw extract scavenged both free radicals more strongly than did -tocopherol and BHT, and the activity of the extract was consistent with the concentration of chlorogenic acid that was present, confirming that this component is a major contributor to the antioxidant activity. The acute toxicity of the Teaw leaf extract was investigated in mice, and it was found that the LD₅₀ of the extract was >32 g/kg. Consequently, this plant is a promising source of a natural food antioxidant.     

Characterization and insecticidal properties of globulins and albumins from Luetzelburgia auriculata (Allemao) Ducke seeds towards Callosobruchus maculatus (F.) (Coleoptera: Bruchidae)

We evaluated the development of Callosobruchus maculatus growing in artificial seeds composed of Vigna unguiculata (cowpea) seed flour mixed with exogenous proteins from Luetzelburgia auriculata. Albumin and globulin fractions from Luetzelburgia auriculata were characterized in terms of protein content, amino acid composition and antimetabolic proteins (trypsin/chymotrypsin inhibitory, porcine pancreatic alpha-amylase inhibitory, lectin activity and presence of chitin-binding proteins). Both fractions were distinct in terms of protein content and diversity as determined by electrophoresis. Lectin activity was present only in the globulins. Neither fraction exhibited inhibitory activity towards porcine pancreatic alpha-amylase but trypsin inhibition was observed. Interestingly, chitin-binding proteins were detected in both protein classes. Albumins had a severe effect upon larval development and were detrimental to insect emergence (LD₅₀=0.4%) while globulins displayed slight toxicity upon larval development and no effect towards insect emergence. The presence of serine proteinase inhibitory activity and chitin binding proteins could explain, at least in part, the harmful effects on C. maculatus development while lectin activity and amino acid availability seem not to correlate with any deleterious effects. Luetzelburgia auriculata would be an interesting source of seed proteins to study behavior of C. maculatus upon infestation and genes coding for insecticidal proteins could become candidates for molecular biology programs devoted to producing transgenic seeds expressing resistance towards the beetle.     

The effects of gender,age and region on macro- and micronutrient contents and fatty acid profiles in the muscles of roe deer and wild boar in Mecklenburg-Western Pomerania (Germany)

Samples of M. longissimus were collected from a total of 203 feral roe deer (n = 118) and wild boar (n = 85) in two regions of Mecklenburg-Western Pomerania (Germany). The muscle lipid saturated fatty acid proportions of roe deer and wild boar ranged between 33 and 49 g/100 g total fatty acids and 31 and 35 g/100 g total fatty acids, respectively. The total n − 3 PUFA proportions in roe deer muscle varied between 8.0 and 14 g/100 g fatty acids, and in wild boar muscle between 2.6 and 6.0 g/100 g fatty acids. The major vitamin E homologue, α-tocopherol, was determined to be between 5.8 and 13.1 mg/kg in roe deer muscles. Lower levels between 1.2 and 4.7 mg/kg were measured in wild boar muscles. The iron and zinc concentrations in roe deer and wild boar muscle ranged from 26.3 to 33.9 mg/kg and from 17.0 to 21.7 mg/kg, and from 13.6 to 39.3 mg/kg and 18.1 to 31.9 mg/kg, respectively.     

Characterisation of 2-Cys peroxiredoxin isozyme (Prx1) from Taiwanofungus camphorata (Niu-chang-chih): Expression and enzyme properties

Peroxiredoxins (Prxs) are a family of antioxidant peroxidases. The functions of Prxs comprises of cell protection against oxidative stress and regulation of cell proliferation. A putative 2-Cys Prx isozyme (Prx1) cDNA was cloned from Taiwanofungus camphorata (commonly known as Niu-chang-chih in Taiwan). The deduced amino acid sequence is conserved amongst the reported Prxs. A 3-D homology structure was created for this Prx1. To characterise the T. camphorata Prx1, the coding region was subcloned into a pAVD10 and transformed into Escherichia coli. The recombinant 6His-tagged Prx1 was expressed and purified by Ni²⁺-nitrilotriacetic acid sepharose. The purified enzyme showed two forms using a 15% SDS–PAGE. The enzyme retained 60% activity at 60 °C for 2.5 min. The enzyme was stable under a broad pH range from 5 to 11. The enzyme showed 57% activity after 40 min of incubation at 37 °C with trypsin. The ability of the enzyme to protect intact supercoiled plasmid DNA from ^·OH induced nicking was demonstrated.     

大连刺参多糖的提取纯化及体外抗氧化活性研究

以大连刺参为原料,多糖提取率为指标,通过单因素实验和响应面试验法优化木瓜蛋白酶提取刺参多糖的酶解工艺条件;以蛋白脱除率为指标,通过单因素实验和正交试验法,优化D-葡萄糖酸-δ-内酯(GDL)对刺参多糖的脱蛋白工艺;并检测经过提取纯化后的刺参多糖的体外抗氧化活性。结果表明,刺参多糖的最佳提取工艺为:加酶量1.60%、pH7.30、温度54.0 ℃,在此条件下刺参多糖提取率为5.34%;最佳脱蛋白工艺条件为:反应温度60 ℃、反应时间2 h、GDL溶液(w/w,20%)加入量2.5 mL,蛋白脱除率为95.8%。提取纯化的刺参多糖清除DPPH自由基、羟自由基、超氧阴离子和ABTS自由基的IC₅₀分别为0.3、4.5、3.9、0.85 mg/mL。刺参多糖浓度为3.0 mg/mL时,ABTS⁺自由基的清除能力最强,达到90.4%,且与阳性对照V_C的清除能力相差不大。说明刺参多糖具有较好的体外抗氧化活性。