Sweetness Index Research Articles

Changes in Sugar Concentrations of Seed and Pod Tissue During Development in Snap and Dry Beans (Phaseolus vulgaris L.)

Sugars, including glucose, fructose, and sucrose, contribute significantly to the flavor and consumer acceptance of snap beans (Phaseolus vulgaris L.). Sugar accumulation and changes in sugar profiles during snap bean development contribute to overall assessments of quality for breeding lines and cultivars. Developing fruit from a diverse group of four snap bean cultivars containing Andean germplasm and one Mesoamerican dry bean cultivar were sampled at 5-day intervals from 10 to 30 days after flowering over 2 years. Glucose, fructose, and sucrose in pod and seed tissue was quantified using high-performance liquid chromatography. Percent seed mass relative to pod mass increased with days after flowering, but the rate of increase was heterogeneous among cultivars. Significant differences in sugar accumulation patterns of mono- and disaccharides were observed with time of development and between pods and seeds. Glucose and fructose decreased rapidly in pods and seeds with time after flowering. In contrast, sucrose concentration increased in pod tissue but remained constant in seeds of the snap bean cultivars with time after flowering. The patterns of changes in pod and seed sugar concentrations with time after flowering were similar among all snap bean cultivars. In contrast to the snap beans, seed sucrose increased with time after flowering in the Mesoamerican dry bean cultivar Puebla 152. No year by day after flowering interactions were observed for sugar accumulation patterns or sugar concentrations. Younger snap beans had the highest sweetness index based on observed sugar concentrations, percent seed mass, and perception of relative sweetness by the human palate. Although mean sweetness varied between cultivars, the rate of decrease in sweetness with time was the same for all five cultivars. These findings indicate that variation for sweetness exists in snap beans and can be exploited by breeding to develop cultivars with a potentially more desirable, sweet flavor.

Barattiere: An Italian Local Variety of Cucumis melo L. with Quality Traits between Melon and Cucumber.

Barattiere, belonging to the Cucumis melo L. species, is a local variety of Puglia (Southern Italy), which is consumed as a vegetable at the immature stage, like cucumber. In this study, three Barattiere populations (‘Monopoli’, ‘Carovigno’ and ‘Fasano’) were evaluated for the main quality traits. All genotypes showed a very light green-yellow colour of flesh, without any difference regarding chlorophyll and carotenoid contents. Carovigno’s Barattiere showed the highest values of dry weight (6.8 g 100 g−1 fresh weight - FW), sugars (45 g kg−1 FW), and sweetness index (7.3), while Monopoli’s Barattiere showed the lowest total phenols content (21 mg kg−1 FW). Fasano’s Barattiere showed the highest content of Zn and Cu (2.3 and 0.3 mg kg−1 FW, respectively), while ‘Monopoli’ showed the highest Ba content (0.3 mg kg−1 FW) and the lowest Mg content (94 mg kg−1 FW). No differences between populations were found concerning the content of Ca, K, Na, B, Mn, and Fe. In conclusion, the quality profile of Barattiere makes this local genotype interesting for its traits, and also suggests its consumption by people with specific dietary requirements.

Physico-chemical and microbial properties of buffalo milk yoghurt drink

Lack of food diversification from buffalo milk causes a lack of public interest in consuming buffalo milk even though it has good nutritional content. Therefore, it is necessary to diversify buffalo milk into yoghurt. This study aimed to make yoghurt from buffalo milk and find the effect of starter concentration and fermentation time on physico-chemical and microbial properties of buffalo milk yoghurt. This research used a completely randomized design with two factors, i.e., concentration starter (3%, 5% and 10%) and fermentation time (8 and 12 hours). Parameters analysed were physico-chemical properties, i. e. acidity, pH, soluble solids, solids non-fat, total solids, sweetness index, astringency index, and microbial properties, i.e. total lactic acid bacteria and total microbial counts. The result showed an increase in values for acidity, astringency index, total lactic acid bacteria counts, and total microbial counts in increased starter concentration and fermentation time. A reverse trend was observed for pH, soluble solids, sweetness index values in increased starter concentration and fermentation time. Total lactic acid bacteria and total microbial count were highest in sample F (10%; 12 hours). Sample A (3%; 8 hours) has the highest total solid (15.4%) and solid non-fat (11.49%).

Sugar accumulation and growth of lettuce exposed to different lighting modes of red and blue LED light

The present study evaluated the growth response and sugar accumulation of lettuce exposed to different lighting modes of red and blue LED light based on the same daily light integral (7.49 μmol·m−2). Six lighting treatments were performed, that were monochromatic red light (R), monochromatic blue light (B), simultaneous red and blue light as the control (RB, R:B = 1:1), mixed modes of R, B and RB (R/RB/B, 4 h R to 4 h RB and then 4 h B), and alternating red and blue light with alternating intervals of 4 h and 1 h respectively recorded as R/B(4 h) and R/B(1 h). The Results showed that different irradiation modes led to obvious morphological changes in lettuce. Among all the treatments, the highest fresh and dry weight of lettuce shoot were both detected with R/B(1 h), significantly higher than the other treatments. Compared with plants treated with RB, the contents of fructose, glucose, crude fiber as well as the total sweetness index (TSI) of lettuce were significantly enhanced by R treatment; meanwhile, monochromatic R significantly promoted the activities of sucrose degrading enzymes such as acid invertase (AI) and neutral invertase (NI), while obviously reduced the activity of sucrose synthesizing enzyme (SPS). Additionally. The highest contents of sucrose and starch accompanied with the strongest activity of SPS were detected in plants treated with R/B(1 h). The alternating treatments R/B(4 h) and R/B(1 h) inhibited the activity of SS, while enhanced that of SPS compared with the other treatments, indicating that different light environment might influence sugar compositions via regulating the activities of sucrose metabolism enzymes. On the whole, R/B(1 h) was the optimal lighting strategy in terms of lettuce yield, taste and energy use efficiency in the present study.

Development of Quantitative Structure-Property Relationship (QSPR) Models of Aspartyl-Derivatives Based on Eigenvalues (EVA) of Calculated Vibrational Spectra

In present study, validated linear quantitative structure-property (sweetness) relationship (QSPR) models were developed, based on an experimental sweetness index and the calculated vibrational spectra of 158 aspartyl-derivatives. The quantum chemical AM1 method was applied to calculate the vibrational spectra of the compounds. The EVA descriptors were derived from the vibrational spectra for a combination of various values of σ (2.5, 5, 10,20 and 40 cm−1) and L (5, 10, 20 and 40 cm−1), which were correlated with an experimental sweetness index of the compounds using the multiple linear regression method. Several QSPR equations were constructed and analyzed. Among the various combinations, the statistically best QSPR equations were achieved when σ =10 and L = 10 were chosen. Four equations were selected as QSPR models, namely, model_1, model_2, model_3 and model_4. Satisfactory statistical values were found for the fit of the training set, R2=0.618, 0.691, 0.605 and 0.604, internal validation Q2=0.540, 0.647, 0.550 and 0.548, and the external predictive measures for the test set, $$ {R}_{pre.}^2 $$=0.614, 0.616, 0.633 and 0.633 were obtained for dubbed 1 to 4 respectively. The application domain of the models was determined. The results of the Y-randomization test of the models support the finding that the statistical values obtained for the QSPR models were not due to just chance. Graphic visualizations of the EVA profiles of some of the selected compounds showed that the presence of hydrophobic moiety in the structure such as those of saturated hydrocarbons, e.g. heptane in ASP_215, tert-butyl in ASP_63, cyclohexane in ASP_201 and pentane in ASP_199, which is related to a high sweetness index, might be monitored in the EVA profiles of aspartyl-derivatives.

Influence of organic, organo-mineral and mineral fertilisers on cane traits, productivity and berry quality of red raspberry (Rubus idaeus L.)

The present study focused on the influence of organic, organo-mineral and mineral fertilisers on primocane growth, floricane properties, yield and berry quality attributes of non-remontant cv. ‘Meeker’ red raspberry (Rubus idaeus L.) during three consecutive years under western Serbian conditions. We used organo-mineral pelleted NPK fertilizer commercially named ‘Excell Orga’ (Excell), soluble crystalline complex fertiliser commercially named ‘Scotts Solinure 1’ (Scotts), water-soluble granulated compound fertiliser commercially named ‘Multi Comp Base’ (MCB), aged mature cattle manure as a organic fertiliser and control variant (without fertilization). Obtained results showed that primocane growth, floricane traits and berry quality traits significantly varied among fertilisers application and among years with exception of berry shape, soluble solids content (SSC), glucose and fructose contents, respectively. Also, in the most cases interaction fertiliser × year was significant. Among fertilisers, MCB and Scotts significantly improved primocane and floricane properties, berry weight and its size, productivity, single and total sugars contents and bioactive compounds (total phenolic and flavonoid contents and antioxidant capacity). Control treatment induced better sweetness index than all fertilisers. Among years, rainy 2014 significantly increased primocane growth, floricane traits, yield, berry weight and size, acidity, pH juice, total sugars and sucrose contents and bioactive compounds content, whereas decreased SSC and ripening index (RI). Warm and dry 2012 decreased primocane growth, yield, some berry physical traits, acidity, total sugars and bioactive compounds, whereas increased number of drupelets, SSC and ripening index value. Manure and Excell exhibited a weak influence on the properties investigated, which were often similar to the control treatment or with minor differences.

Morphological and chemical analysis of peach fruits in three different farming systems

This study aimed to access the commercial and the sensorial quality of the “flat peaches” variety grown in three farming systems: conventional and organic (“with compost” and “without compost”) in Gafsa, located at the south-west of Tunisia. Tests were performed on 18 and 22 ripe fruits randomly harvested at full maturity stage based on morphological and chemical traits according to peach descriptors and to some previous fruit analysis. Highly significant differences were noted between the three farming systems for some peach morphological characters. According to the peach descriptors, the organic peaches (“with compost” and “without compost”) had a good attractiveness (7) and very firm flesh (9) compared to the conventional ones (3 and 5, respectively). The highest mean fruit weight (89.3 g) was obtained in organic cropping system “with compost.” A significant difference between cropping systems was noted for the majority of chemical parameters. The juice percentage was higher in organic fruits (≥ 55.0%) than in conventional ones (> 43%). The soluble solids content and the total sugars were the highest in organic peaches “without compost” (13.5 and 11.8% Brix, respectively). In organic peaches “with compost,” the titrable acidity and the total acidity were high (73.5 meq/l of juice and 0.4%, respectively) and the ripening and the sweetness indexes were low (0.1 and 1.6, respectively). The increases in the titrable and total acidities were concomitant with a decrease in juice pH values. The titrable acidity was significantly and negatively correlated with the ripening index (r = − 1.0*). This latter was also significantly and positively linked to the sweetness index (r = 1.0*). The organically grown peaches exhibited the highest quality traits (attractive, firm, big, juicy, etc.). Peaches were acid when grown organically system “with compost” and sweet “without compost.” These results may incite more the Tunisian farmers to produce organic peach and to develop more this agricultural system in Tunisia.

Towards a better management of the gustatory quality of pineapple using the Simpiña crop model

Fruit quality has become increasingly important in fruit production, and improving the quality of products is an economic, public health, and scientific concern. The gustatory quality of fruit at harvest is affected by environmental conditions and management and can be highly variable. Our objective was to use the SIMPINA model, linked to SIMPINA - Sugar and SIMPINA - TA to identify combinations of cultural practices that optimize the gustatory quality of pineapple at harvest in the main areas of production on Reunion Island. SIM PINA - Sugar simulated total soluble solids (TSS) during fruit development. Titratable acidity (TA) was simulated with a statistical model linking periods during fruit development where climatic variables (rainfall, global radiation and temperature) affect TA of pineapple at harvest. The optimal sweetness index TSS/TA was used to select combinations of cultural practices that improve gustatory quality. Globally, to reach the optimal TSS/TA, the set of practices, e.g., optimum months for planting, dates of forcing, planting density and irrigation varied according to the diversity of climatic conditions in the main areas of production studied. Cultural practices selected lead to the production of large fruits (>700 g) and the model consistently identified harvest dates in the warm season as the time when the optimal TSS/TA was obtained regardless of area of production.

A new sensory sweetness definition and sweetness conversion method of five natural sugars, based on the Weber-Fechner Law

This study’s aim is to establish a new sensory sweetness definition and conversion method for five sugars. A “closed-type” question based on triangle test and paired comparison was used for sensory evaluation. The absolute threshold and nine sensory difference threshold values were determined and used to generate a sweet sensory difference strength curve. Defining absolute threshold of sucrose sweetness as 1, the sucrose sweetness at any concentration could be calculated via the curve. After taking the logarithm of each curve, sweetness index was calculated as 1, 1.12, 0.94, 1.29, and 1.25 for sucrose, glucose, fructose, lactose and maltose, respectively. Based on this, each sugar concentration and sweetness could be converted and calculated. Single sugar and mixed-sugars sweetness comparison experiments verified the new sweetness index and sweetness values were more accurate (83.3–100%) than those reported in previous studies. Therefore, this new definition and conversion method established more reliable references for sweet taste sensory applications.

Hyperspectral imaging technique to evaluate the firmness and the sweetness index of tomatoes

Hyperspectral imaging technique to evaluate the firmness and the sweetness index of tomatoes

Calibration modelling for non-destructive estimation of external and internal quality parameters of ‘Marsh’ grapefruit using Vis/NIR spectroscopy

Consumer preference for fruit without disorder influences purchase of fruit at both local and international markets. Recent trends in horticulture show that consumer preference is influenced by assurance that external appearance is linked with rewarding internal sensory quality. Therefore, the need for non-destructive evaluation of external and internal quality parameters is important. This study was conducted to develop and test calibration models for integrated prediction of external and internal quality of ‘Marsh’ grapefruit. Visible to near infrared (Vis/NIR) spectroscopy (Vis/NIRS) was used to acquire spectral information from 522 intact fruit. Reference quality parameters such as colour indices (luminosity (L*), greenness (a*) and yellowness (b*)), rind dry matter (DM), rind total phenolics concentration, BrimA, carbohydrates, sweetness index (SI) and total sweetness index (TSI) were obtained using conventional methods. Principal component analysis was applied to analyse spectral data to identify outliers. Savitzky-Golay second derivative with second order polynomial was employed as pre-processing method to correct light scattering properties of the spectra. The spectra were subjected to a test set validation by categorising the spectra into calibration (60%) and validation (40%) sets. Partial least square regression was used as chemometric tool to develop models for predicting each parameter. The model validation results showed that external and internal quality parameters of grapefruit could be predicted with satisfactory accuracy with R2 value of 0.99 for rind quality parameters (L*, a*, b*, DM) and 0.77, 0.99, 0.99 for BrimA, SI and TSI, respectively. The residual predictive deviation (RPD) results for L*, a*, b*, DM, BrimA, SI and TSI were 64.1, 61.4, 123.4, 12.9, 1.4, 9.0 and 13.9, respectively. Vis/NIR calibration and validation results demonstrated that quality parameters of ‘Marsh’ grapefruit could be predicted using Vis/NIRS.

Impact of Sharka disease on tree growth, productivity and fruit quality of apricot (Prunus armeniaca L.)

In this study, the influence of Sharka disease, caused by Plum pox virus (PPV), on tree growth, yield attributes, financial losses, fruit physical properties, nutritive compounds, phenolic and flavonoid contents and antioxidant power was evaluated in a susceptible apricot (Prunus armeniaca L.) genotype. The results showed that Sharka significantly reduced tree growth, yield and economic results in PPV infected trees in comparison with PPV uninfected trees. The Sharka did not change fruit and stone weight and fruit shape, but significantly decreased flesh rate and flesh firmness. Soluble solids content (SSC) and titratable acidity (TA) were higher in symptomatic fruits, whereas ripening and sweetness index, sucrose and total sugars contents were smaller in fruits from PPV infected trees. Differences in content of invert sugars were not significant. Finally, PPV significantly reduced total phenolic (TPC) and total flavonoid contents (TFC) and total antioxidant capacity (TAC) in comparison with their contents in fruits from PPV uninfected trees.

Foliar application of potassium-based fertilizer improves strawberry fruit quality

Among the different mineral nutrients, potassium (K) is recognized as the macronutrient that most strongly affects the quality parameters of crops. An adequate K nutrition is in fact associated with increased fruit size, enhanced nutraceutical properties (e.g., content of sugar, organic acids, antioxidants), improved color and increased shelf life for many agricultural products. Previous studies have shown that, in controlled conditions, the foliar application of K-based fertilizers during the fruit development period could improve fruit quality; however, it is not clear whether such positive results can also be obtained in field-cultivated plants. For these reasons, the aim of the present study was to assess if the repeated applications of K-based fertilizers during the production period (mid-June to late August) might affect the quality parameters of strawberry (Fragaria × ananassa 'Murano') fruits. Frigoplants, transplanted in April, were cultivated in grow bags on cocopeat (8 plants per linear meter) and treated foliarly spraying K(2)SO(4) (6 g L(-1)) either once or twice a week. Control plants were sprayed with distilled water. As expected, foliar K-fertilization increased the K concentration by 8-11% in fruits and by 7-5% in leaves according to the frequency of application (once and twice a week, respectively). In addition, strawberry fruits exhibited an enhanced total soluble solids content (approximately 12%) and sweetness index (approximately 13%). Conversely, other nutraceutical compounds (e.g., phenolics, flavonoids and flavonols) as well as the fruit yield were not affected by K treatments, regardless the fertilization levels. In conclusion, results here presented show that at the field scale the foliar K-fertilization during the development of strawberries can enhance the quality and the nutraceutical value of fruits.

The effects of plant growth-promoting rhizobacteria (PGPR) on the growth and quality of strawberries

Several studies have shown the benefits of plant growth-promoting rhizobacteria (PGPR) on plant mineral nutrition, suggesting their possible application as biofertilizers. PGPR can stimulate plant growth, increase plant resistance to abiotic and biotic stresses and might thus have a positive effect on fruit quality. The aim of this research was to evaluate and compare the effects of beneficial microorganisms, supplied either as pure culture (Azospirillum brasilense) or as a commercial mixture (Effective Microorganisms - EM™), on the growth and quality of strawberry (Fragaria ananassa 'Elsanta') fruits. Strawberry frigo-plants were hydroponically grown either in a complete nutrient solution, or in a nutrient solution inoculated with A. brasilense or with EM for 10 weeks. At harvest, biometric parameters, such as shoot and root fresh weights, and yield parameters, like number of fruits plant-1 and fruit weight, were recorded. Growth parameters (e.g., biomass, leaf area) were not affected by the rhizobacteria. Even though PGPR-inoculated plants showed slightly reduced fruit yields in terms of average number of fruits plant-1, they delivered larger fruits as compared to untreated control. Fruits obtained from PGPR-inoculated plants also had a higher sweetness index in comparison to control fruits. The content of total phenols showed no significant difference between the different samples, whereas the concentration of flavonoids and flavonols was higher in fruits harvested from A. brasilense-inoculated plants. In addition, PGPRs also influenced the uptake and allocation of nutrients in fruits, in particular increasing the concentration of micronutrients.

Fertilization strategies as a tool to modify the organoleptic properties of raspberry (Rubus idaeus L.) fruits

Abstract Raspberry cultivation is increasing all over the world, being these fruits highly appreciated not only for their taste but also for their high content in bioactive compounds. However, the short shelf-life of these fruits limits their fresh consumption and industrial use to a defined time frame. For this reason, setting agronomic strategies aimed at extending the fruit shelf-life represent a prerequisite to ensure the presence of high-quality raspberries on the market for a prolonged time. Therefore, aim of this work was to assess the influence of different nutritional regimes (over-fertilization with NH4+, Si or B) on the firmness and the potential extension of the shelf-life as well as on the quality of raspberry fruits. Raspberry canes (Rubus idaeus) cv. ‘Lagorai Plus’ were grown in a high tunnel plastic greenhouse and starting from middle July to September raspberry fruits were collected. The over-fertilization with NH4+, Si or B lead to higher yields, increased colour indexes, firmness, sucrose content and sweetness indexes. Furthermore, the fertilizations led to an improved shelf-life due to a significant reduction of fruit darkening and fruit weight loss, which was particularly evident at the end of the incubation. The results of this work highlighted that the modification of the nutritional status of raspberries by adding either Si, B or NH4+ could be helpful in obtaining fruits with improved qualitative parameters. In particular, an increase in the sweetness index and firmness of fruits as well as an extension of the shelf-life could be beneficial for the attractiveness of consumer and also for the possibility of using fruits in the industrial transformations. Moreover, considering the role of Si and B in human health, the bio-fortification programs can become particularly interesting, thus opening the way for new market perspectives of these fruits in addition to the traditional ones.

Changes in the levels of selected organic acids and sugars in apple juice after cold storage

Apples are a source of sugars, acids, and various biologically active compounds, such as phenolic compounds, which are responsible for most of the antioxidant activities of the fruit. The aim of this study was to evaluate how the cold storage of apple fruits affects the nutritional composition of selected organic acid and sugar content in juice in comparison to juice from fresh fruits. Statistical differences were confirmed between the content of citric acid, malic acid, total acid, pH, sucrose, fructose and glucose in juice from fresh fruits and from juice stored for 140 days. No statistical differences were observed between juice from fresh fruit and juice from fruits stored for 140 days in the content of acetic acid, tartaric acid, total sugar and sweetness index.

BEVERAGES BASED ON RICOTTA CHEESE WHEY AND FRUIT JUICES

For studying antioxidants, sugars and organic acids compositions and their impact on Sourness Index (SI) and Total Sweetness Index (TSI), beverages were produced by blending Ricotta-cheese whey (RCW), by-product of Ricotta cheese production, with fruit juices. Pear-RCW had higher malic acid and sorbitol, blueberry-RCW higher citric acid, total phenolics and anthocyanin pigments, apple-RCW higher sucrose and fructose, and strawberry-RCW higher glucose. Blueberry-RCW had the highest SI and the lowest TSI, while apple-RCW had the lowest SI and the highest TSI. Higher quality beverages may be obtained by using apple juice (‘Yellow’ type) and the apple:blueberry (50:50) blend (‘Red’ type).

Agro-morphological characterisation and evaluation of a Serbian vineyard peach [Prunus persica (L.) Batsch] germplasm collection

Seventy-five vineyard peach [Prunus persica (L.) Batsch] accessions, obtained by seed propagation and originating from different regions of Serbia, were characterized using a set of 39 agro-morphological traits. The evaluation was carried out over a 3-year period in a vineyard peach collection situated at the Radmilovac Experimental Station, owned by the Faculty of Agriculture, Belgrade University. To investigate diversity, descriptive statistics and multivariate analyses were used. Most studied traits showed high variability. The variability of descriptive traits was highly pronounced for fruit ground and flesh colour; regarding metric traits, the highest variation was recorded for trunk circumference, petal width, flower density, fruit set, fruit weight, sweetness index, fruit taste and fruit flavour. According to PCA, traits with high discriminating power were those related to flower type, colour and size, fruit size and presence of over colour, tree height, ripening time and fruit taste. The cluster analysis grouped accessions into three main clusters and a few sub-clusters. Agronomically-important traits allowed a clear separation between the clusters, while morphological traits had almost no impact on this. This study provided information that is important for assessing the biodiversity of vineyard peach accessions, to develop guidelines useful for the description, classification and conservation of valuable local germplasm. Moreover, the phenotypic variability in the vineyard peach collection was found to be very high, suggesting there is extensive genetic diversity available for peach cultivar and rootstock breeding programs.

Effect of a New Remediated Substrate on Fruit Quality and Bioactive Compounds in Two Strawberry Cultivars

The dredging materials extracted from seaports, considered as contaminants, can be a problem at the time of removal from the environmental point of view. Currently, there is a progressive exhaustion of peatland; and therefore, a substitute for peat mass as a growing substrate is required. These reasons make it a priority to seek solutions in both directions. For this reason has been want to show the suitability of dredged sediment, after being bioremediated for 3 years, as a new substrate in agriculture. Thus, were studied the behavior of dredged remediated sediments on fruit quality and bioactive compounds of two strawberry cultivars “Camarosa” and “Monterrey”. The strawberries were grown on three substrate-based treatments: peat 100%, sediment 100% and 50% both (mixture). Fresh weight, firmness, soluble solids content, titratable acidity, maturity index, sugars, sweetness index, acids, vitamin C, sugars-acids ratio, antioxidant activity and total phenol content were determined for each treatment. The results indicated that no significant differences were established on fruit quality within different treatments. The strawberries grown under dredged remediated sediment (DRS) and Peat-DRS substrate (mixture 50%) showed a high content in vitamin C, total phenols and antioxidant activity, also had the highest sweetness index and a good firmness. The present study has shown that the used of DRS as a growing substrate for strawberries are a valid alternative to satisfy the progressive shortage of the traditional substrates and should be further investigated in order to modify European legislation on growing substrates for agricultural uses.

Free Sugar and Organic Acid Content of the Unripe and Ripe Jujube (Zyziphus jujuba) as Honey Plant

The fruit of five cultivars (Mudeung, Geumseong, Wolchul, Bokjo and Boeun) of jujube (Zyziphus jujuba) were analyzed to estimate free sugar and organic acid content in unripe and ripe jujube cultivars. Glucose, galactose, fructose and sucrose were the major sugar components of jujube. In this study, we observed that sucrose, glucose and fructose content increased during fruit ripening. The highest sucrose content of jujube fruit was 20.54g/100g in ripe Wolchul cultivar. The sweetness index, which plays important role of taste, was also calculated from the content of sucrose, glucose and fructose. The sweetness of jujube fruit increased with fruit growth and development. The highest sweetness of jujube fruit was 116.32 in ripe Geumseong cultivar. Main organic acid detected in jujube were citric acid, malic acid and fumaric acid. As the weight, diameter and soluble solids of Zyziphus jujuba fruit were increased with the progress of ripening, organic acids were also increased. The highest citric acid and malic acid content in jujube fruit were 14.64g/100g (Boeun, ripe) and 19.33g/100g (Geumseong, ripe), respectively.