Different Concentrations Of Sucrose Research Articles

The Influence of Sucrose on Biomass and Glycosides Content of Callus Cultured from the Leaves of Stevia rebaudiana Bertoni

Stevia rebaudiana Bertoni contains diterpenoid steviol glycosides that have no adverse impact on blood sugar levels despite being 300 times sweeter than sugar. This study aimed to investigate the rate of callus induction from stevia leaves and the content of glycosides when changing the sucrose percentage in the culture medium.. Murashige and Skoog (MS) culture medium supported by 4.0 mg/l naphthalene acetic acid (NAA) and 1.0 mg/l benzyl adenine (BA) was used, and different concentrations of sucrose (2, 3, 4, 5 and 6%) were tested .The extraction of glycosides from leaf and callus tissues was performed by using methanol. Extracted glycosides were analyzed by high-performance liquid chromatography (HPLC). The results showed significant influences of sucrose on callus initiation. The concentration of 3% sucrose had the highest fresh and dry weight. No callus was induced in the MS medium with a high concentration of sucrose (5% and 6%). However, the highest glycoside content, stevioside and rebaudioside were obtained from callus treated with 4% concentration followed by 3% sucrose the treatment . The highest fresh and dry weight average was obtained with a 3% concentration of sucrose, this treatment also increased the concentration of glycosides in the callus twice as much as in the leaves, and concentrations of 3% and 4% of sucrose gave very similar concentrations of glycosides in callus in terms of being double what was found in the leaves something which may aid in the development of a stevia glycosides based industry.

Clonal propagated 'Ek Pothi Lehsun' as a potential antifungal agent against Candida sp.

'Ek Pothi Lehsun', also known as snow mountain garlic, is a type of garlic grown in the high mountainous region of Jammu and Kashmir state of India. The present study aimed to develop a protocol for propagating snow mountain garlic in-vitro using corm seed as an explant. The study also assessed the antifungal potential of in vitro-grown bulbils against different Candida species. Four different concentrations of NAA and 2,4-D were tested for their effectiveness in promoting root formation, and eighteen different combinations of BAP (µM), KN (µM) and TDZ (µM) were investigated for effective proliferation of shoots with varied lengths. Shoot with maximum length (5.03±1.40) was obtained in MS medium containing 1.0 µM TDZ after 24 days of inoculation, whereas MS basal media was found effective for rooting plantlets. Rooted micro shoots were acclimatized successfully in hardening treys with a percent survival of nearly 80%. Seven different concentrations of Sucrose, i.e. 5%, 7%, 10%, 15%, 17%, 20%, and 25% were investigated for effective bulbil formation. Bulbil with a maximum diameter of 0.86 cm was obtained in 20% sucrose-containing MS media in 5 days. Further, the antifungal potential of aqueous extract (TC-SMG) of in vitro grown bulbils was investigated against three Candida sp. A zone of inhibition of 22.30±0.33 mm, 17.3±0.33 mm and 19.3±0.33 mm was observed against C. albicans, C. tropicalis and C. glabrata respectively, by using 200 mg/mL extract after 24 hrs depicting the remarkable potential of TC-SMG as an antifungal agent. In vitro culture of snow mountain garlic has demonstrated promising antifungal properties against Candida species.

The Development of an Improved Medium for the In Vitro Germination of Corylus avellana L. Pollen

The European hazelnut (Corylus avellana L.) is a self-incompatible, wind-pollinated species of significant economic-productive interest, mainly cultivated between the Mediterranean basin and the Black Sea. Hazelnut breeding programs and high cropping in commercial orchards are necessarily linked to the availability of fertile pollen with wide germinability and high viability. The objective was to develop an improved method to determine the germinability of pollen, comparing the results with those found in the literature. Pollen germinability was firstly evaluated on a wild-type accession using boric acid (H3BO3), calcium nitrate (Ca(NO3)2), magnesium sulfate (MgSO4), potassium nitrate (KNO3), casein hydrolysate and different concentrations of sugars, including sucrose (10, 15 and 25%) and two monosaccharides, glucose (15%) and fructose (15%). The optimal composition included 15% sucrose in a semi-solid medium composed of 1% animal gelatin, containing collagen. This formulation was then tested on three cultivars of commercial interest, evaluating the effect of different concentrations of sucrose. The comparison between different in vitro germination methods showed that the hanging drop technique in a semi-solid medium provides a statistically higher germination index compared to the liquid and solid/agarized techniques. This study proposes an easy-to-use medium for the in vitro germination of Corylus avellana L. pollen.

In vitro microrhizome induction in Acorus calamus L., a commercially important aromatic medicinal plant

Acorus calamus L., is a leading aromatic medicinal plant that produces pungent aromatic rhizomes that are valued worldwide as an important herbal medicine and is one of the main ingredients in several polyherbal formulations used for neurological and metabolic disorders. The present investigation aims to develop an efficient protocol for in vitro microrhizome induction in A. calamus for the large-scale production of disease-free planting material for commercial purposes. In vitro derived shoots were initiated on MS medium supplemented with different concentrations of sucrose alone (3–10 %) and different concentrations of sucrose (6 % and 7 %) with varying concentrations of BAP alone (0.5–2 mg/L) and combinations with IAA (0.5 and 1 mg/L) and NAA (0.5 and 1 mg/L) were carried out for the microrhizome induction experiments. In different concentrations of sucrose used, healthy and disease-free microshoots of A. calamus were obtained in MS media supplemented with 7 % sucrose followed by 6 % sucrose. The highest shoot length (24.79 ± 0.03 cm) and microrhizome size (4.98 ± 0.03 cm length and 399.60 ± 0.37 mg fresh weight) were obtained in MS solid medium supplemented with 1 mg/L BAP and 0.5 mg/L NAA with 7 % sucrose followed by the same hormone concentration with 6 % sucrose (shoot length-23.68 ± 0.03 cm, microrhizome length- 4.68 ± 0.03 cm and fresh weight of microrhizome-376.60 ± 0.57 mg). The developed protocol can be used for large-scale production of disease-free propagules without rooting and acclimatization and enhance the production of true-to-type planting material.

Cryopreservation of sessile oak (Quercus petraea (Matt.) Liebl.) plumules using aluminium cryo-plates: influence of cryoprotection and drying

Background Quercusseeds that are recalcitrant to desiccation and freezing temperatures cannot be stored in gene banks under conventional conditions. However, the germplasm of some recalcitrant seeded species can be stored in liquid nitrogen (–196 °C). Unfortunately, for many species, among them for almost the whole genus Quercus, an effective cryostorage method is still unknown. In this study, we propose a successful cryostorage protocol for Quercus petraea (Matt.) Liebl. germplasm using plumules (a shoot apical meristem of an embryo) frozen on aluminium cryo-plates.ResultsThe plumules isolated from the acorns of ten provenances were prestored in 0.5 M sucrose solution (for 18 h). To form alginate beads (one plumule per bead), the plumules were placed in the wells of a cryo-plate and embedded in calcium alginate gel. For cryoprotection, the encapsulated plumules were immersed in cryoprotectant solution containing 2.0 M glycerol and different concentrations of sucrose (0.8–1.2 M) for 40 min at 25 °C and desiccated under a laminar flow cabinet for 1.0–4.0 h. Cryo-plates with plumules were directly immersed in liquid nitrogen and then cryostored for 30 min. For rewarming, cryo-plates with plumules were immersed in 1.0 M sucrose solution and rehydrated for 15 min at 25 °C. Survival rates varied from 25.8 to 83.4 were achieved after cryoprotection in 1.0 M sucrose solution and the drying of plumules for 2 h. The in vitro regrowth rate of cryopreserved plumules varied among provenances and was 26–77%.ConclusionsThis study presents, for the first time, a successful, simple and effective protocol for the cryopreservation of Q. petraea germplasm that could be used in gene banks. The experiment was successfully repeated on seeds from various provenances, each yielding similar, good results. However, seed quality and storage time after harvesting are important factors in plumule regrowth after cryopreservation.

Optimized Protocol for in vitro Pollen Germination in Brinjal (Solanum melongena L.)

Background: Understanding floral and pollen biology is essential for efficient artificial hybridization in hybrid seed production. This knowledge helps ensure proper fertilization of the ovary and optimal fruit and seed set. Selecting suitable pollen parents and preserving pollen for future use allows for better control and optimization of hybridization practices in brinjal breeding programs. To achieve this, a robust protocol for pollen collection and viability testing is necessary to monitor pollen quality in the field and during storage. This information is crucial for maintaining desired characteristics and genetic traits in the resulting hybrid seeds. Methods: This study; aimed at optimizing the pollen germination assessment protocol for brinjal. The step wise modification standard medium composition was done, the optimal growth condition was tested and in vivo predictions were made. So, the study aimed to standardization of media for in vitro pollen germination evaluate and viability in brinjal in ambient as well as cold storage conditions. The pollen germination was tested in vitro as well in vivo, by incubating the pollen grains for 3 hours at 25°C in different concentrations of sucrose, boron and agar media and distilled water at interval of 12 hours. Result: The most favorable germination of fresh pollen was achieved with a treatment consisting of 1% Agar, 12% Sucrose and 300 ppm Boron. Comparing the two storage conditions, pollen stored in the refrigerator exhibited higher in vitro germination percentages compared to ambient storage conditions. The highest in vitro pollen germination and viability percentages were observed in fresh pollen collected within 12 hours (95.00%). As the duration of pollen storage increased in both storage conditions, the in vitro pollen germination decreased. This decline in in vitro pollen germination was reflected in the in vivo fertilization fruit set percentage. The highest fruit set percentage was observed when pollen was stored in the refrigerator (64.52%) and when female flowers were pollinated with pollen stored for less than 12 hours (84.66%).

Thermal resistance of selected strains of Salmonella spp. isolated from eggs and sesame seeds

In this study, we investigated the effect of food matrices on the heat tolerance of Salmonella strains and evaluated the impact of sugar and fat on the heat resistance of these strains. We tested ten strains of Salmonella spp. isolated from eggs and ten from sesame seeds. The conducted research revealed that S. Poona 4193 and S. Oranienburg 4182, isolated from sesame seeds, exhibited the lowest average decimal reduction times (D-values) at 60 °C and 65 °C. Conversely, strains of S. Enteritidis 3927 (eggs), and S. Mbandaka 4297 (sesame seeds), demonstrated the highest D-values. In the next stage we examined the effect of different concentrations of sucrose (5%, 10%, 15%) and sesame oil (10%, 25%, 50%) on the tolerance of Salmonella to high temperatures. We then selected specific concentrations of sucrose and oil in the medium for each strain based on the highest D-value obtained. The 4297 strain exhibited the highest D-value with 5% sucrose and 10% oil, 4193 strains with 10% sucrose and 25% oil, 4182 with 10% sucrose and 10% oil, and 3927 strain with 10% sucrose, and 50% oil. Our studies indicated that the heat resistance of Salmonella is highly dependent on the specific strain.

Análise da degradação foliar de Lisianthus (Eustoma grandiflorum) na pós-colheita por espectroscopia de reflectância VIS-NIR-SWIR

ABSTRACT: It is known that floriculture is very important for the world economic scenario. Nevertheless, the vase life of cut flowers is determined by a short time span. This study evaluated the spectral behavior during leaf degradation of lisianthus (Eustoma grandiflorum) flower stems in the postharvest, in different preservative solutions, and estimating its leaf pigments by hyperspectral data. Lisianthus floral stems were subjected to preservative solutions with different concentrations of sucrose, glucose, phytohormones and deionized water. Leaves from these stems were collected every 4 days for further hyperspectral analysis. Spectra was determined in laboratory with a sensor collecting at the range of 350-2500 nm. In order to analyze the use of the spectra to detect the performance of the preservative solutions, statistical tests were used at each wavelength. Pigment prediction was assessed by the CAR/CLF ratio (Ratio between Carotenoids and Chlorophyll) from the spectral curves, using PLSR and RRMSE. The glucose-based solutions registered positive effects on the preservation of floral stems, especially at the dose of 180 g/L. The solutions based on sucrose and phytohormones registered similarities in the spectral curves among the doses, demonstrating equality in leaf preservation. The discriminant analyses demonstrated there was statistical difference in the spectral responses in the doses for each solution used. The CAR/CLF ratio had reasonable coefficients of 0.6 and RRMSE below 6.99%. The hyperspectral analyses presented a potential for the evaluation of leaf degradation in lisianthus floral stems in different pulsing solutions used in the postharvest.

Impact of carbon source for the synthesis of α-amylase in rice callus culture

Various carbon sources such as fructose, glucose, sucrose and maltose were tested at different concentrations to control enzyme synthesis in callus culture. Among them, 3% maltose was found to be the best carbon source for effective synthesis and secretion in the callus induction medium. The effect of various carbon sources on the synthesis of α-amylase in rice callus culture was studied. The features of the production of α-amylase in rice callus culture were studied on media containing as a carbon source a natural polysaccharide – starch and the end products of its enzymatic hydrolysis – maltose and glucose. A study of the dynamics of growth of callus culture of rice embryos on media with various carbon sources showed that the greatest growth of calli during the cultivation cycle was observed in the variant with glucose and corresponded to an almost 7-fold increase in cell mass. Using different concentrations of sucrose, it was found that the onset of induction of synthesis and secretion of cathodic isoforms of AMY1 α-amylase in rice suspension cells coincided exactly with the moment of depletion of the carbon source in the nutrient medium. The synthesis of the anodic forms of the AMY2 enzyme was constitutive.

Study on the preference of rosella mangrove syrup with different concentrations of sucrose

Syrup products are preferred considering the tropical climate of Indonesia. One of the mangrove fruits that can be processed into syrup is pedada (Sonneratia caseolaris) which is combined with the natural colour of roselle flower petals. With the addition of roselle, the resulting syrup colour becomes attractive with a pink color. The manufacture of roselle mangrove syrup requires the addition of the right sugar. In this study, the manufacture of 1 kg of mangrove fruit was added with 3 concentrations of sucrose sugar (1; 1.5, and 2 kg). Tests were carried out by measuring antioxidant activity, the value of sucrose content, viscosity, and hedonic test. The test results showed that the value of sucrose content increased along with the addition of sucrose sugar to the syrup, namely 65.61 to 71.46%. The value of this sucrose content has met the SNI for syrup. The highest antioxidant value in the 2 kg sugar treatment was 79.58. In the study of the viscosity, the highest value at treatment with the composition of 2 kg sugar additional. However, the panelists preferred syrup with a sugar composition of 1.5 kg with the highest score marked on the hedonic test.

Pulsing Effect of Sucrose and Sodium Hypochlorite on Vase Life of Cut Chrysanthemum cv Arcticqueen Flower

An experiment was executed to investigate the role of different concentrations of sucrose and sodium hypochlorite as pulsing solution on post harvest storage life and other characteristics of cut chrysanthemum cv Arctic queen flower after harvest. The experiment was framed as completely randomized design with factorial concept with three levels of sucrose (5, 10, 20 %) and with 50 ppm NaOCl with 3 replications. The output of the experiment revealed that flower weight (8.26 g), water uptake (13.76 g), fresh weight change (123.76g), and maximum vase life (10.23 days) was achieved in 10% sucrose for 4 hrs pulsing treatment.

Effect of sucrose in strawberry micro-propagation using platform bioreactor under temporary immersion system

The study was carried out in the tissue culture laboratories at the College of Agriculture / University of Kufa during the period from April 2020 to October 2021 where the aim was to assess the efficiency of micropropagation of strawberries by adding different concentrations of sucrose (30, 40 and 50 g.L-1 ) to the nutrient medium in combination with different cultivation systems: Semi-solid media system and temporary immersion system using the Plantform bioreactor. The results showed that both the highest concentration of sucrose and the culture system under the medium immersion, individually or combined, were the highest and significantly effective in increasing the rate of number of shoots (runners), leaf content of macro and minor elements, total soluble sugars, plant pigments and fresh weight of biomass. Generally, the highest values were recorded in the shoots grown in liquid media supplied with 50 g.L-1 sucrose under temporary immersion in the PlantForm bioreactor compared with those grown in semi-solid media. Keywords: Fragaria × ananassa, micro-propagation, plant nutrition, tissue culture, PlantForm bioreactor

Kombucha analogs from maqui juice: Consortium age and sugar concentration effects on anthocyanin stability and its relationship with antioxidant activity and digestive enzyme inhibition.

The fermentation of maqui juice (MJ), by incorporating kombucha as a starter culture, produces beverages with variable and stable anthocyanin contents. The metabolic effect of kombucha starter cultures obtained at different fermentation times was explored on the anthocyanin stability of maqui (Aristotelia chilensis (Mol.) Stuntz) juice supplemented at different concentrations of sucrose and fermented at different times. The stability of anthocyanins was associated with the levels of catechin detected in the fermentation system. This study concludes that the fermentation of MJ with sucrose (10%) and kombucha consortium of 7-days old, promotes the release and accumulation of phenolic compounds that act as co-pigments, with the best response in quality parameters of beverages such as color intensity, tone, hyperchromic effect, and a significant bathochromic shift. Finally, the additive effect of phenolic constituents with stable anthocyanins, confers to kombucha analogs an outstanding antioxidant quality and inhibitory effects on key enzymes in digestive processes.

Sucrose Concentration and Fermentation Temperature Impact the Sensory Characteristics and Liking of Kombucha.

Kombucha is a fermented tea beverage consumed for its probiotics and functional properties. It has a unique sensory profile driven by the properties of tea polyphenols and fermentation products, including organic acids. Fermentation temperature and sucrose content affect the fermentation process and the production of organic acids; yet less is known about their impacts on the sensory profile and consumer acceptance. Thus, we aimed to examine the impact of sucrose concentration and fermentation temperature on sensory attributes and liking. For this study, kombucha tea was fermented at three different concentrations of sucrose and fermented at two temperatures for 11 days. Fermentation was monitored by pH, brix, and titratable acidity, and consumers (n = 111) evaluated the kombucha for sensory attributes and overall liking. The fermentation temperature resulted in significant differences in titratable acidity, with higher temperatures producing more organic acids, resulting in higher astringency, and suppressed sweetness. The lower fermentation was reported as significantly more liked, with no difference in liking between the 7.5% and 10% sucrose kombucha samples. Fermentation temperature had the greatest impact on the sensory profile rather than sucrose concentration, which had a greater effect on the fermentation rate and production organic acids.

Optimizing Different Medium Component Concentration and Temperature Stress Pretreatment for Gynogenesis Induction in Unpollinated Ovule Culture of Sugar Beet (Beta vulgaris L.)

The great economic importance of sugar beet determines the ongoing biotechnological studies conducted worldwide to improve the technology of obtaining doubled haploids (DHs) using the method of unpollinated ovule culture in vitro. To improve the induction of gynogenesis, we tested the effect of thidiazuron (TDZ), temperature bud pretreatment, different concentrations of sucrose, and culturing on liquid or solid medium. Three genotypes were tested in this study. The use of TDZ at a concentration of 0.4 mg/L in solid IMB (induction medium for Beta vulgaris) induction nutrient medium with 3 g/L phytagel, 50 g/L sucrose, 200 mg/L ampicillin and cultivation at 28◦C in the dark produced up to 16.7% induced ovules. The liquid nutrient medium of the same composition induced up to 8% ovules. Increasing TDZ concentration to 0.8 mg/L resulted in reduction or total inhibition of gynogenesis, depending on the genotype. Reducing the sucrose concentration to 20 g/L or increasing it to 80 g/L was not effective. In all three genotypes, the absence of temperature pretreatment of buds (5–6 °C) showed the best results. The plant regeneration with MS nutrient medium of 20 g/L sucrose, 3 g/L phytagel, 1 mg/L 6-benzylaminopurine (BAP) and 0.1 mg/L gibberellic acid (GA3) resulted in up to seven shoots from one induced ovule in the most responsive genotype. We showed by flow cytometry, chromosome counting and chloroplast number assessment that all regenerant plants were haploid (2n = x = 9).

In vitro propagation of red ginger (Zingiber officinale Roxb. var. Rubrum) in different concentrations of sucrose and growth regulator

In vitro culture of ginger is highly influenced by medium formulations such as sucrose and growth regulator. A micro-propagation was done to determine the influence of sucrose concentration and growth regulator on in vitro growth of red ginger. Sterilized sprouts with shoot tips collected from the rhizome were cultured on formulated media of MS medium containing three diverse concentrations of sucrose and different types and combinations of growth regulators for shoot differentiation. The number of days required for buds to break varies from 13 - 36 according to the sucrose concentration, type, and combinations of growth regulators. Among the formulated medium, the MS medium contained 30 gr of sucrose and BA 1 mg.l-1 induced bud sprouts in about 13-14 days. The sucrose concentration and growth regulator also had significant differences in shoot number, leaf number, and root number. Interaction of BA 1 mg.l-1 and sucrose 30 g.l-1 produced the highest number of shoots per explant (6.33) and the number of leaves per shoot (3.72). Auxin promotes the growth of intact roots as the medium supplemented with NAA yielded a higher number of roots, however, rooting was also observed in all formulated media after two passages of subculturing.

Effectiveness of Pollen Germination Media for Improving Storage Potential in Pomegranate (Punica granatum) Germplasm

Viable pollen grains with the ability to germinate after fertilization are necessary for fruit and seed formation. Pollens are sensitive to environmental conditions and quickly lose their viability after anthesis. In vitro storage potential of pollen grains depends on species, genotype, flower type, and storage conditions. The present study's objective was to evaluate pomegranate germplasm's storage potential and to study germination media's influence on short-term stored pollen's germination percentage. Pollens of fifteen pomegranate genotypes were collected and stored at 4 °C for 30 days. Pollen viability was assessed using in vitro pollen germination by the agar-Petri method. The germination media was composed of different concentrations of sucrose, boric acid, and agar. The results showed that germination media (12.5% sucrose + 0.2% agar) supplemented with 10 ppm boric acid gave the highest germination among all cultivars. Among genotypes, maximum (58.3%) germination was observed in Desi and Kandhari red pollens, and minimum (16.3%) was observed in Sandhora. The concentration of boric acid in germination media influenced pollen germination. The highest pollen germination was found at 10 ppm, followed by 5 ppm, and the lowest germination was found in media with no boric acid. Conclusively genotypes show variation in storage potential, and germination media influences post-storage germination rate. The utilization of effective germination media can increase the pollen germination rate for pomegranate genotypes.

Effects of sucrose concentration and membrane filter number on the growth and volatile compounds of micropropagated Lippia rotundifolia Cham. plantlets

Lippia rotundifolia Cham. is a medicinal species, native to Brazilian mountainous regions, with leaves rich in monoterpenes. The objective of this study was to evaluate the effect of different concentrations of sucrose in MS medium with a natural ventilation system using porous membranes on the growth and contents of volatile compounds in L. rotundifolia plantlets. The experimental design was completely randomized, with 12 treatments, consisting of a factorial system of four ventilation systems and three sucrose concentrations. The treatments were a system with no porous membrane (NMS) and three natural ventilation systems (AMS) containing one, two, and four porous membranes. The sucrose concentrations were 0, 15, and 30 g L −1 . The natural ventilation systems were superior to NMS. The natural ventilation system with two and four porous membranes and 15 g L −1 sucrose in MS medium led to higher in vitro growth rates in L. rotundifolia . AMS using manufactured porous membranes was found to be a more efficient in vitro cultivation method than NMS. The ventilation system with four porous membranes and a sucrose concentration of 15 g L −1 was the most efficient, since an increase in the photosynthetic rate and less evaporative water loss were observed in this ventilation system. Volatile organic content was influenced by ventilation systems and sucrose concentrations. Major compounds myrcene, limonene, myrcenone and ocimenone were identified. AMS4 and presence of sucrose (15 and 30 g L −1 ) increased the myrcene and ocimenone content. The myrcenone content was favored by NMS without sucrose. Overall, the alternative membrane system with 15 g L −1 of sacarose can be recommended in the in vitro culture method of L. rotundifolia. • Alternative membrane systems enhancement dry weight of plantlets. • Four membrane filters without sucrose and 15 g L −1 promote an increase in leaf area. • Myrcene and ocimenone content increase using four membrane filters and sucrose. • Nonporous membrane system without sucrose have a higher myrcenone content.

Characterization of levansucrase produced by novel Bacillus siamensis and optimization of culture condition for levan biosynthesis

Levan has attracted interest due to the potential health benefits associated with its prebiotic, biological, and functional properties. However, the production of levan is expensive due to its high resource requirements. With the growing demand for levan, it is vital to determine suitable cultivation condition for its production and reduce costs accordingly. The present study characterized the enzyme levansucrase produced by a novel strain of Bacillus siamensis and optimized the conditions for the biosynthesis of levansucrase and levan. The crude levansucrase enzyme production by B. siamensis was induced at a specific temperature in a medium containing different concentrations of sucrose, fructose, and glucose to evaluate transfructosylation and hydrolysis activities. Crude levansucrase significantly increased transfructosylation relative to hydrolysis activity at 37 °C in a medium containing 20% (w/v) sucrose. Both transfructosylation and hydrolysis activities were inhibited in glucose and fructose containing medium. Purification and characterization of the levansucrase were performed by precipitating the enzyme with ammonium sulfate solution, purified anion-exchange chromatography, and analyzed by Sodium Dodecyl Sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The results showed the molecular weight of the enzyme to be approximately 30 kDa with specific activity at 15.95 U/mg, corresponding to a protein purification efficiency of 11.47 and a yield of 78.75%. The optimal culture condition for the purified-levansucrase activity for levan biosynthesis was obtained at 37 °C after 48 h, at pH 6.0 in 50 mM phosphate buffer and 20% (w/v) sucrose. The study demonstrated the optimized condition for levan biosynthesis utilizing the B. siamensis that can serve as a model for various commercial and industrial applications for efficient levan production.

Using correlation matrices to standardise sweet liking status classification

Distinct hedonic patterns of sweet taste liking have been widely recognised for more than half a century. Despite there being a growing consensus on the role of Sweet Liking Status (SLS) in food choice behaviour, current classification methods for this phenotype generally lack consistency. Using a large dataset (n = 865), the present study applied Agglomerative Hierarchical Clustering (AHC) followed by correlation matrices as a validated and robust method for SLS classification by using five sucrose solutions (3, 6, 12, 24 and 36 %). As demonstrated in the present study, AHC alone was not a sufficient method to generate reliable SLS clusters. Following a validated correlation matrix approach, three distinct consumer clusters were identified: High Sweet Likers (HSL), Medium Sweet Likers (MSL) and Low Sweet Likers (LSL). Robust mean liking scores were generated for each of the three clusters across five different concentrations of sucrose. The results suggested that in order to enable more efficient and comprehensive SLS classification, a correlation-based approach for SLS classification using the validated liking means provided in the current study should be adopted in future research. In addition, a rapid three-solution method (3 %, 12 % and 36 %) was also explored as a simplified and more efficient way of classifying participants for SLS. The rapid three-solution method accurately classified the majority of HSL, MSL and LSL within the dataset. The data showed a good level of agreement between the rapid three-solution method and validated five-solution method, therefore suggesting that a rapid three-solution method can be considered when exploring the two hedonic extremes (HSL and LSL) when additional noise in the data can be tolerated.