SOFTENING AND BIOCHEMICAL CHANGES OF SAPOTE MAMEY FRUIT (POUTERIA SAPOTA) AT DIFFERENT DEVELOPMENT AND RIPENING STAGES

We investigated some of the physicochemical and biochemical factors associated with flesh softening of sapote mamey fruit during development and ripening. The activities of pectinmethylesterase (PME), polygalacturonase (PG) and β‐galactosidase (β‐GAL) enzymes were measured in fruits harvested at different development stages, and postharvest in two production seasons. The textural changes were most noticeable at the preclimacteric stage in ripening fruit. The water‐soluble pectin (WSP) increased at a different rate than firmness decreased. No correlation between PG or PME activity and changes in firmness was observed in ripening fruits, though a low correlation was seen between β‐GAL activity and softening in climacteric stage. Greatest loss of firmness occurred in climacteric stage. Fruit pulp softening was not dependent on a single enzyme activity.     

MINERAL COMPOSITION OF MEDLAR (MESPILUS GERMANICA) FRUIT AT DIFFERENT STAGES OF MATURITY

Abstract The mineral composition of medlar fruit collected (June 15 - October 8) in Turkey at five stages of development was studied. In the fruit, 32 minerals were analyzed and 16 minerals (Al, Ba, Ca, Cu, Co, Fe, K, Li, Mg, Mn, Na, Ni, P, Sr, Ti and Zn) were present at detectable levels. The ripe medlar fruit was richest in potassium (7370 μg/g dry wt), calcium (1780 μg/g dry wt), phosphorus (1080 μg/g dry wt), magnesium (661 μg/g dry wt) and sodium (183 μg/g dry wt). During the fruit development, Al, Ba, Fe, Mn, P, Sr, and Zn were highest in August (unripe fruits) while the concentrations of K, Ca, Mg and Cu gradually decreased throughout development. The ripe medlar fruit is an important source of nutritionally needed minerals and trace elements, in particular Ca, Cu, Fe, K, Mg, Mn, Na and Zn, for human populations in southeastern Europe, Turkey and Iran.     

SENSORY AND CHEMICAL EVALUATION OF MANCHEGO CHEESE AND OTHER CHEESE VARIETIES AVAILABLE IN THE SPANISH MARKET

Chemical and sensory characteristics of 28 different cheeses acquired in the Spanish market were evaluated. Principal Component Analysis (PCA) of the physico‐chemical results showed that the cheeses were separated into three groups: hard, soft and elastic cheeses, while PCA of the sensory results classified the same cheeses into four groups, distinguishing between two types of hard cheese (Manchego cheese with Appellation of Origin and other Spanish hard cheeses). Sensory Analysis differentiated between cheeses of very similar physicochemical characteristics, the attributes that contributed most to differentiation being fragility, adhesiveness, pasty and spicy. Some correlations were obtained between sensorial and chemical variables, the most significant being hardness versus total nitrogen (TN) and versus dry matter (DM), and fragility versus water activity.     

CHANGES IN CHEMICAL COMPOSITION OF 'CAVENDISH' BANANA (MUSA ACUMINATA) DURING RIPENING

Green 'Cavendish' bananas were exposed to ethylene for 16 h and the subsequent development of ripening at 20°C was followed in terms of skin color, respiration and ethylene production. At six stages of ripeness, as determined by skin color, pulp tissue was analysed for firmness and for water, protein, fat, individual sugars, starch, dietary fibre, organic acids, ash, soluble solids, pH, vitamin C, thiamin, riboflavin, niacin, carotenes, sodium, potassium, calcium, magnesium, iron and zinc; energy content and edible weight were calculated.     

MECHANICAL PROPERTIES AND VISCOELASTIC CHARACTERISTICS OF TWO VARIETIES OF YAM TUBERS (DIOSCOREA ALATA)

The main mechanical properties and viscoelastic characteristics of two different cultivars of yam have been measured in this work. Using an Instron machine, some different tests has been applied: puncture, uniaxial compression and bending in order to calculate the parameters: maximum stress of penetration, stress and strain at fracture, deformability modulus and the constants a and b from the Peleg model. It is concluded that the Pico de Botella cultivar has a fracture stress higher (0.57 MPa) than the Diamante 22 cultivar (0.31 MPa). Also, the degree of deformation at fracture is higher (32 versus 21%). In relation with the constants from the Peleg viscoelasticity model, there are no differences between cultivars, both having the same value of the asintotic stress ( a =  0.43) and very similar for the relaxation stress rates (Pico de Botella, b =  0.03 and Diamante 22, b =  0.02).

PRACTICAL APPLICATIONS

Information on mechanical properties of yam that has not been reported in the literature.     

DIFFERENT RATES OF DEVELOPMENT OF α-AMYLASE IN DISTAL ENDOSPERM ENDS OF GERMINATED (MALTED) CHARIOT AND TIPPER BARLEY VARIETIES

Chariot Barley had a faster malting rate than Tipper. Even when the total levels of the aleurone-produced enzyme α-amylase were similar in both Chariot and Tipper, the distal ends of the grains of Chariot developed α-amylase at a faster rate than the corresponding endosperm ends of Tipper. The excised aleurone layers of Chariot and Tipper had similar potentials to produce α-amylase. Therefore the faster rate of development of α-amylase in the distal ends of the grains of Chariot may reflect faster transport of active gibberellic acid through the aleurone layer. Differences in the rates of transport of gibberellic acid through the plasmodesmata of the aleurone layer may determine the efficiency of production and distribution of endosperm-degrading enzymes during malting. The transport of gibberellic acid in the aleurone layer was facilitated by high moisture levels.     

ASSESSMENT OF THE ANTIMICROBIAL POTENTIAL OF ROSELLE JUICE (ZOBO) FROM DIFFERENT VARIETIES OF ROSELLE CALYX

The dried calyx of Hibiscus sabdariffa (Roselle) from different varieties, roselle purple dark red, roselle light red, roselle bright red and roselle deep red, was processed into a nonalcoholic drink known as “zobo” in Nigeria. The zobo drinks were prepared into two concentrations each, 2 and 15%, respectively, from each variety. The physicochemical parameters of the zobo drinks at different concentrations were determined. There was significant difference in the values for pH and vitamin C, while there was no significant difference in the values for total titratable acidity and °Brix. For 2% concentration zobo, the absorbances were the following: “roselle” purple dark red, 2.88; roselle light red, 2.52; roselle bright red, 0.72; and roselle deep red, 0.64, respectively. For 15% concentration of zobo, the absorbances were the following: roselle purple dark red, 27.00; roselle light red, 18.00; roselle bright red, 3.30; and roselle deep red, 3.00, respectively.     

EFFECTS OF WATER STRESS ON THE PROXIMATE COMPOSITION AND MINERAL CONTENTS OF SEEDS OF TWO LUPINS (LUPINUS ALBUS AND LUPINUS MUTABILIS)

Because mineral composition data for lupins subjected to water stress (ws) are incomplete, it is essential to analyze those seeds in order to assess the quality of potential food source for both human and animal nutrition. So, we have performed chemical proximate analysis and determined the mineral profile of seeds from two lupins subjected to ws period and compared with seeds from well‐watered (ww) plants. From the above results we can conclude that the values obtained fall within the range of values reported for both species (at ww conditions) and no significant (P > 0.05) differences were found in nutritional composition and mineral content between both lupins. Ws period was responsible for a significant increase in sugar, ash, both macroelements (Ca, Na, K, Mg) and microelements (Fe, Zn, Mn, Cu) as well as phytate content. The results obtained are relevant for selection of better mineral nutritive value of seeds from lupin species.     

RESEARCH NOTE: A COMPARISON OF THE CHEMICAL COMPOSITION OF ZANDER (SANDER LUCIOPERCA) LIVING IN DIFFERENT LAKES OF TURKEY

In the present work, the proximate compositions, minerals and trace element contents of zander ( Sander lucioperca ) caught from two lakes (Beyşehir Lake and Seyhan Dam Lake) of Turkey were compared. There were significant differences between moisture and lipid contents, although there were no statistically significant differences between crude protein and ash contents. The mineral and trace elements determined were Na, K, Ca, P, Mg, Zn, Cu, Fe, Pb and Se. Although Na and Fe contents of zanders in two different lakes were different from each other ( P <  0.01), we found no statistically significant differences in terms of Mg, Ca, P, Cu, Pb, Se, Zn contents ( P >  0.01). Among the minerals analyzed, K was the highest followed by P, Ca, Na and Mg. The most abundant trace elements were Zn, Fe, Cu, Se followed by Pb, and these elements were below the limits proposed by Turkish Food Codes for human consumption in the meat of zander.

PRACTICAL APPLICATIONS

This present study includes information about the nutritional value of zander, which lives in the fresh water lakes of our country and of which people are fond and is being exported. The comparison of the proximate, mineral and trace element contents of the same species which are caught in two different lakes has been made. In the scope of human nutrition, in accordance with the minerals which have got much importance, it involves useful information about what the position of this fish is, and whether it contains any risk due to trace elements. Furthermore, concerning this subject, it will also light the way for studies to be made in the future.     

CONSUMER SENSORY TEST OF SEVEN VARIETIES OF RICE IN OSH (PILAF) AT FOUR DIFFERENT LOCATIONS IN UZBEKISTAN

This study was done to determine if consumers in Uzbekistan would accept the Long Grain and Bengal rice varieties that are grown in South East Missouri for preparation of Osh. Three hundred and fifty eight consumers from Tashkent, Fergana, Namangan and Andijan participated in a consumer hedonic test involving overall acceptability of the rice varieties Avangard, Bengal, Chinese, Calrose, Devzira, Long Grain and RiceTec in Osh. A nine-point hedonic scale was used to record acceptance of the participants. Analysis of variance and internal preference mapping were performed on the consumer data. Overall, it was seen that Devzira was the most accepted rice variety probably because of its popularity among the local Uzbeks. The mean acceptance score for Long Grain and Bengal (6.1 and 6.0, respectively) showed that the two rice samples were also acceptable to the majority of the consumers, which proved its potential to be exported to Uzbekistan from the U.S.A.

PRACTICAL APPLICATIONS

The Central Asian countries that were part of the former Soviet Union import rice from countries such as Turkey and Thailand to supplement the needs of their general population. The per capita consumption of rice in Uzbekistan (∼12.0 kg/person/year) exceeds the production of rice there. Uzbekistan is an arid region that is not suitable for crops such as rice because it requires a lot of water. Other staple crops like cotton and wheat require less water, and hence fare better in this region. The U.S.A. has become a major player in the rice export industry, and is looking at these Central Asian countries to import rice while encouraging the governments there to grow other staple crops such as cotton and wheat.     

THE RIPENING PROCESS OF KIWIFRUITS (ACTINIDIA DELICIOSA) GROWN IN CATALONIA, SPAIN

The ripening process of kiwifruits (Actinidia deliciosa), was studied to determine the best harvesting time and storage potential for commercial shipping. The samples were taken from two representative interior and coastal areas of “Maresme” (Catalonia) with known and controlled agroclimatic features. Relative humidity and temperature conditions were controlled for cold storage. The samples for analyses were taken during the maturation phase of the plant (52 days) as well as in cold storage (182 days). Soluble solids (SS) concentration, flesh firmness, sugar composition, total acidity and vitamin C content were measured, the first three parameters were indicative of the degree of ripeness. At the moment of reaching the peak concentration of sugar and SS (optimal eating time) the protein, lipid, content of mineral elements (K, Fe, Mg and Ca) and the parameters specified above were determined.     

真菌寡聚糖单糖组成(HPLC)分析及诱导抗病活性初步研究

采用高效液相色谱法（HPLC）法对5种用1-笨基2-甲基-5-吡唑啉酮（PMP）衍生后的单糖，进行了分离分析，并采用该方法对两种真菌源寡聚糖的单糖组成进行了分析。同时初步研究了真菌源寡聚糖的诱抗活性。结果表明两种真菌源寡聚糖均有诱抗活性，葡萄友霉寡聚糖（寡聚糖Ⅱ）的诱抗活性高于葡萄链格孢寡聚糖（寡聚糖Ⅰ）的诱抗活性；用高效液相色谱法（HPLC）对单糖衍生物实现了良好的分离，且该方法可作为实际样品中痕量单糖分析的常规方法；两种寡聚糖中均含有果糖，D-甘露糖，葡萄糖，D-半乳糖和D-阿拉伯糖五种单糖，寡聚糖Ⅰ中该5种单糖的摩尔比为3：5：10：4：1，寡聚糖Ⅱ中该5种单糖的摩尔比为1：5：3：2：2。     

PHYSICAL, CHEMICAL, FLAVOR AND SENSORY CHARACTERISTICS OF TWO SWEET CHERRY VARIETIES GROWN IN 'VALLE DEL JERTE' (SPAIN)

Volatile compounds and physical, chemical and sensory characteristics of two sweet cherry varieties autochthonous from ‘Valle del Jerte’, in the Southwest of Spain, during 1995 and 1996 seasons were investigated. ‘Pico Colorado’ had higher values of lightness, chroma, hue, firmness and Brix/acid ratio than