Primary metabolites in the leaves and fruits of three pear cultivars during the growing season

2007 ◽  
Vol 87 (2) ◽  
pp. 327-332 ◽  
Author(s):  
Metka Hudina ◽  
Mateja Colarič ◽  
Franci Štampar

Primary metabolites (sugars and organic acids) in leaves and fruits of the pear cultivars Conference, Concorde and Williams were investigated during the growing season in Slovenia. Leaves were sampled 15 times from Apr. 25 to Oct. 22. Fruits were sampled seven times from Jun. 14 to Aug. 23. The contents of sugars (glucose, fructose, sucrose, and sorbitol) and organic acids (malic, citric, shikimic, and fumaric) in leaves and fruit were determined by high performance liquid chromatography (HPLC). Similar dynamic patterns were found in the glucose, fructose, sucrose and sorbitol in leaves and fruits of the genetically related cultivars Conference and Concorde. Leaf sugar was low at the beginning of the growing season when the leaves were not completely developed. Generally when sucrose increased in leaves it decreased in fruits. At the end of June the total sugar content in leaves reached its peak then rapidly decreased. At the same time, total sugar in fruits increased. From the beginning of August, total sugars in fruits increased regardless of the sugar content in leaves and likely due to decomposition of starch. After harvest, the contents of individual sugars (glucose, fructose, sucrose, and sorbitol) in the leaves decreased until the beginning of October when, just prior to leaf drop, they increased in all cultivars. Key words: Pyrus communis, sugars, organic acids

2005 ◽  
Vol 15 (3) ◽  
pp. 668-672 ◽  
Author(s):  
Teri A. Hale ◽  
Richard L. Hassell ◽  
Tyron Phillips

The refractometer has been proposed as a rapid, inexpensive technique for determining sugar levels in fresh sweet corn (Zea mays). High performance liquid chromatography (HPLC) analysis of sugars in three phenotypes (su, se, and sh2) of sweet corn harvested at three maturities indicated that sucrose content was highly correlated with the total sugars (R = 0.95). Sucrose and total sugar concentration were significantly different among all phenotypes. Soluble solids concentration (SSC) was high in su and se compared to the lower SSC of sh2. Early, mature, and late harvested samples differed in sucrose and total sugar content. Sugar concentration varied within phenotypes at each maturity level. Sh2 indicated no difference in sucrose and total sugars at early and mature harvests, but increased at late harvest. In contrast, sucrose and total sugar content decreased between early and mature harvests, then increased to highest levels at late harvest in se and su phenotypes. Overall, phenotype SSC increased significantly from early to late harvests, probably due to increased water-soluble polysaccharides in the su and se cultivars. Unlike other crops, a negative relationship was found in sweet corn between SSC and sucrose or total sugars, with an overall correlation of –0.51. This relationship was most affected by maturity, especially mature and late harvested sweet corn. Among phenotypes, sucrose, total sugar, and SSC were poorly correlated. Our results indicate that a refractometer should not be used to estimate total sugars or sucrose of sweet corn.


HortScience ◽  
2004 ◽  
Vol 39 (4) ◽  
pp. 879A-879
Author(s):  
Teri Hale* ◽  
Richard Hassell ◽  
Tyron Phillips

Taste panel perception and preference of sweetness in three phenotypes (su, se and sh2) of sweet corn harvested at three maturities (early, mature and late) were compared to refractometer measurements and HPLC analysis of fructose, sucrose, and glucose. Panelist rating of sweetness and acceptability significantly correlated with HPLC analysis. These correlations were found for sucrose and total sugars present (for sweetness, r2 = 0.70 and 0.61; acceptability, r2 = 0.64 and 0.55). Sucrose significantly correlated with the total sugars present (r2 = 0.95). The panelists' perception of flavor also correlated significantly with the amount of sucrose present and total sugars (r2 = 0.66 and 0.59, respectively). Sucrose content was significantly different between se, sh2 and su, with sh2 having the highest level. Taste panels indicated this difference but showed not significant differnece between se and sh2 acceptablity. Su was only acceptable to panelists at early maturity. °Brix did not reflect the taste panels scores and HPLC measurements postively. Soluble solids and taste panel scores were negatively correlated in both the panel's perception of sweetness and acceptability (r2 = -0.66 and -0.66, respectively) which indicates that as panel scores decreased °Brix increased. Comparison of soluble solids to HPLC analysis, indicate that °Brix was negatively correlated to sucrose and total sugar content, and that as soluble solids increased, the sucrose or total sugar concentration remained constant or decreased. Soluble solids measurements have been positively correlated with sucrose levels in other crops; but this was not the case with sweet corn.


2020 ◽  
Vol 16 (4) ◽  
pp. 530-542 ◽  
Author(s):  
Kahina Djaoud ◽  
Lynda Arkoub-Djermoune ◽  
Hocine Remini ◽  
Sabrina Sait ◽  
Myriam Tazarourte ◽  
...  

Background: In Algeria, important quantities of secondary date variety (Phoenix dactylifera L.) are generated in each campaign; their chemical composition is similar to that of commercial dates. The present work aims to valorize this common date variety (Degla-beida) which is often poorly exploited. Methods: In this context, we tried to prepare syrup from the secondary date variety and evaluate the effect of conventional extraction (CE) or water bath extraction (WBE) and alternative extraction (microwaves assisted extraction (MAE) and ultrasound-assisted extraction (UAE)) on its total sugar content (TSC), using response surface methodology (RSM). Then, the analysis of individual sugars was performed by high performance liquid chromatography (HPLC). Results: Maximum predicted TSC recoveries under the optimized conditions for MAE, UAE and CE were 233.248 ± 3.594 g/l, 202.889 ± 5.797 g/l and 233.535 ± 5.412 g/l, respectively, which were close to the experimental values: 233.796 ± 1.898 g/l; 202.037 ± 3.401 g/l and 234.380 ± 2.425 g/l. HPLC analysis revealed high similarity in the sugar composition of date juices obtained by MAE (60.11% sucrose, 16.64% glucose and 23.25% fructose) and CE (50.78% sucrose, 20.67% glucose and 28.55% fructose), although a large difference was detected for that obtained by UAE (0.00% sucrose, 46.94% glucose and 53.06% fructose). Conclusion: Microwave-assisted extraction was the best method for the preparation of date syrup with an optimal recovery of total sugar content. However, ultrasound-assisted extraction was the best one for the preparation of date syrup with high content of reducing sugars.


2019 ◽  
Vol 15 (5) ◽  
pp. 476-483 ◽  
Author(s):  
Mohammed Adel Mesbahi ◽  
Mohammed Redha Ouahrani ◽  
Abdelkrim Rebiai ◽  
Djilani Ghamem Amara ◽  
Atef Chouikh

Background: Honey is generally evaluated by physicochemical analysis of its constituents. The manipulation of honey and its possible adulteration is reflected in many of its physicochemical properties. Objective: In this study, samples of Zygophyllum album L honey produced in El-Oued, Algeria, were characterized based on their melissopalynology, physicochemical and antioxidant properties, also polyphenol content. Methods: The physicochemical parameters of honey, such as density, moisture content, pH, free acidity, electrical conductivity (EC), total sugar content, color intensity, water insoluble solids content, hydroxymethylfurfural (HMF), ash, specific rotation, were measured. A number of antioxidant tests were performed to determine the antioxidant properties of Zygophyllum album L honey samples. The polyphenol in the Zygophyllum album L honey was measured by spectrometric determination based on folin-ciocalteu’s method. The identification and quantification of phenolic compounds were carried out by RP-HPLC (high-performance liquid chromatography). Results: All honey samples contained monofloral (67.83-91.89%) pollen belonging to Zygophyllum album L. The results of physicochemical parameters of analyzed honeys were: pH 4.33, moisture 17.2%, free acidity 41.96 meq/kg, electrical conductivity 0.408 mS/cm, HMF 11.89 mg/kg, Ash 0.246 (%), specific rotation -8.21. The Zygophyllum album L honey was extra white amber. The total sugar content ranged from 81.5 to 83. Honey samples contain high levels of gallic acid (252.53±15.56 mg/kg honey), chlorogenic acid (124.71±10.09 mg/kg) and low amounts of total polyphenol (467.82±46,98 mg GAE/kg). Conclusion: Physicochemical parameters (total acidity, pH, moisture, dry matter, ash, and qualitative hydroxymethylfurfural) were within the approved limits established by International Honey Commission.


1989 ◽  
Vol 61 (2) ◽  
pp. 113-122
Author(s):  
Aino-Maija Evers

The effects of different fertilization practices on the glucose, fructose, sucrose, taste and texture of carrot cv. Nantes Duke Notabene 370 Sv were studied in field experiments carried out in southern Finland in 1985 and 1986. The effects of unirrigated and irrigated placement and broadcast fertilization, NPK fertirrigations without basic fertilization, NPK fertirrigations with NPK basic fertilization, and PK placement with N fertirrigations were compared. Further, the effects of single application were compared with those of split applications. Sugar analyses were made by high performance liquid chromatography, and sensory evaluations were performed for taste and texture. The results were analysed by contrast analysis. In 1985, fertilization and fertilization practices had no effects on sugar contents. In 1986, the unfertilized treatments had a tendency to yield higher glucose and fructose, and thus also total sugar contents than did the fertilized treatments on the average. Placement fertilization had a tendency to increase the glucose content as compared to NPK fertirrigations. No significant differences or tendencies were found in sucrose content. The glucose and fructose contents were higher in 1985 than in 1986. The sucrose content was mainly opposite, being higher in 1986.Weather conditions were more favourable for photosynthesis in 1986 than in 1985. The mean total sugar content in fresh weight was 7.8 % in 1985 and 6.7 % in 1986. Indicative results of taste and texture are presented. The sugar content in organically cultivated carrots did not differ from that of conventionally grown carrots, but the taste was worse.


CORD ◽  
2008 ◽  
Vol 24 (1) ◽  
pp. 7
Author(s):  
Bandupriya H.D.D.

Changes in soluble sugars, sugars profile, starch and proline levels in inflorescence rachillae from individual coconut palms were investigated during inflorescence development with the aim of determining a possible correlation between these characters and morphogenic potential of inflorescence tissues. Rachillae for analysis were collected from unopened inflorescences of -1 to -13 stages (considering the youngest open inflorescence as 0 stage) in decreasing order of maturity (–1 stage is the most mature stage whereas –13 is the most immature stage). Important differences among the maturity stages were observed for total sugars. In very tender inflorescences (-13 and -12), the total sugar content was very low whereas a gradual increase was observed from -11 to -7 stages, with  -7 stage having the highest level. The total sugar content in more mature inflorescences was relatively low, with the exception of -2 stage, which had a high total sugar content. In regard to sugar profiles, sucrose, fructose and glucose were the main soluble sugars present in coconut inflorescence and sucrose was the most abundant sugar in -5 to -9 maturity stages. Total soluble sugars and sucrose in maturity stages from -5 to -9 showed a very similar variation and significantly higher levels of sucrose were observed in -6 to -8 stages. The proline content in the mature stages, -1 to –3, was significantly lower than in the other stages with no significant variation in the stages –4 to –11. The pattern of variation in starch content was similar to that of proline which decreased with increasing maturity of inflorescence. In view of the results obtained, the higher accumulation of sucrose and total sugars in -6, -7 and -8 stages may have some significance in morphogenesis, especially as an energy source. The 10 cm length inflorescence that responds better for callusing falls within this range. Thus total sugar and sucrose content may be possible biochemical markers for assessing the morphogenic potential of inflorescence explants.


2021 ◽  
Author(s):  
Rahul Govinda Kolwate ◽  
Ashish Ashok Uikey ◽  
S.R. Shegokar

Background: During present investigation burfi was prepared from different combinations of cow milk khoa and pumpkin pulp [viz., 100:00 (T1), 75:25 (T2), 70:30 (T3), 65:35 (T4) and 60:40 (T5)] and the samples were subjected to sensory evaluation, chemical analysis and cost was computed considering the ingredients and processing costs. The pumpkin pulp (as per treatments) and sugar (30% by weight of khoa) were mixed with khoa at different stage of khoa preparation. Then, the mixture was heated till burfi was obtained. Methods: For preparation of burfi fresh cow milk was obtained from Livestock Instructional Farm, Akola. The milk was standardized to 4.0 per cent fat and 9.0 per cent SNF for the preparation of burfi. The khoa blended with pumpkin (Cucurbita pepo) pulp at different ratios, the product without using pumpkin pulp served as control. The burfi was analyzed for chemical composition (viz., fat protein, total sugars, ash and total solids). The organoleptic attributes of burfi were analyzed in terms of its flavor, body and texture and color and appearance, wherein the total score was out of 100; the judging panel comprised on 5 members. Result: The total sensory scores of burfi obtained were 87.81, 90.46, 95.46, 92.99 and 84.30 for the treatment T1, T2, T3, T4 and T5 respectively. The burfi prepared from various combinations involving use of up to 70 per cent cow milk khoa in blend with pumpkin pulp was found acceptable. The fat content of burfi’s was 19.61, 15.40, 14.38, 13.40 and 12.37 per cent, protein content was 14.89, 12.64, 12.11, 11.61 and 11.04 per cent, total sugar content was 32.78, 36.73, 37.59, 38.45 and 39.31 per cent, ash content was 2.69, 2.55, 2.53, 2.49 and 2.45 per cent, total solids content was 69.94, 67.30, 66.60, 65.94 and 65.17 per cent for the treatment T1, T2, T3, T4 and T5 respectively. The fat, protein, ash and total solids of burfi tended to decrease while total sugar and moisture content tended to increase with an increase in the level of pumpkin pulp used as additive. The per kg cost of production of pumpkin based burfi decreased with increasing level of incorporation of pumpkin pulp in burfi formulation i.e. ₹ 240 (100:00 khoa), ₹ 204.51 (75:25, khoa: pulp), ₹ 199.11 (70:30 khoa: pulp), ₹ 194.33 (65:35 khoa: pulp), ₹ 189.25 (60:40, khoa : pulp) for the treatment T1, T2, T3, T4 and T5 respectively. The most acceptable burfi i.e. T3 was computed to be priced at ₹ 199.11 per kg.


Food Research ◽  
2020 ◽  
Vol 4 (S1) ◽  
pp. 187-195
Author(s):  
F.N. Mohd Nawawi ◽  
I.S. AhmadFadzly ◽  
Noor Safiqah Ain Safingi N.S.A. ◽  
N. Mustafa Khalid ◽  
M.F. Md Noh ◽  
...  

High glycaemic index foods were found to increase the risk of getting diabetes, obesity, cancer and cardiovascular disease. This study aimed to determine the in vitro glycaemic response and sugar composition of selected food types, which include sugars, rice-based meals and traditional cakes and desserts (kuih). The food samples were purchased prepared and analysed using High Performance Liquid Chromatography (HPLC) to determine the sugar composition. The samples were also prepared and assayed using validated in vitro digestion method to determine the estimated glycaemic response. The in vitro method used 0.25g total available carbohydrate, which was established by Clegg Anthrone method. Among the studied samples, the total sugar content was icing sugar (100%), which has the highest percentage, nasi kerabu (7.49%) and kuih lapis (42.20%) for sugars, rice-based meals and traditional kuih, respectively. Dialyzable glucose concentration for the sugar samples was highest in the sugar in sachet (3.47 mg/mL) and lowest in the sugar with stevia (0.49 mg/mL). For the different types of rice-based meals, the highest dialyzable glucose concentration was in nasi lemak (13.06 mg/mL), and the lowest was in nasi kerabu (12.33 mg/mL). While for traditional kuih, kuih lapis (10.53 mg/mL) and kuih keria (6.30 mg/mL) were highest and lowest in the dialyzable glucose concentration, respectively. Significant correlations exist between dialyzable glucose concentration (at 120 minutes) and sugar composition (p<0.05) for the rice-based samples. Among the traditional kuih samples, sucrose content and total sugar content was correlated significantly. However, no correlation exists between dialyzable glucose concentration and sugar composition for the selected sugar samples. Factors such as particle size and presence of phytochemical in sugars, available nutrients (starch, protein and fat) in kuih and cooked dishes as well as the amount of added sugar in food are vital factors that affect the in vitro glycaemic response of the studied samples.


HortScience ◽  
1992 ◽  
Vol 27 (4) ◽  
pp. 333-335 ◽  
Author(s):  
William M. Walter

The sugar content of five sweetpotato [Ipomoea batatas (L.) Lam.] cultivars (`Centennial', `Cordner', `Georgia Red', `Jewel', and `Sweet Red') was measured by high-performance liquid chromatography (HPLC) and compared to the sugar content of the cellular sap measured by refractive index (RI). The HPLC and RI sugar contents were measured at harvest, after curing, and during storage. Changes in the sugar content, as determined by the RI, were found to be linearly related to changes in the sugar content of cell sap and tissue, as measured by HPLC, indicating that this method can be used to monitor changes in postharvest total sugar content.


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