Influence of sucrose reduction on fouling during the production of dulce de leche

In this Research Communication we focus the food industry´s broad tendency to decrease sugar content in food products onto dulce de leche (DL) and examine the influence of sucrose reduction on the detrimental deposits formed during the production process. The method used to identify the impact produced directly on the heat exchanger during the production of this product with low sucrose content required varying the quantity of sucrose in the milk. Different percentages of sucrose (20, 15, 10, 5 and 0% w/w) were submitted to the DL concentration process in a process simulator. After concentration, the quantification of the deposits formed in each was carried out and these deposits were characterized according to their composition. Methods such as Kjeldahl, Pregl-Dumas and sem-EDS were used. Thus, the work highlights the need to change the product manufacturing process due to changes in the formulation that directly impact the formation of deposits in the equipment used (fouling). This deposit changes significantly in relation to its quantity as well as in relation to the composition and chemical characteristics as the gradual reduction of the sucrose content in the production takes place. Therefore, these impacts must be considered in order to maintain better manufacturing and ensure efficient cleaning of equipment.

Mixed modeling for fiber yield genetic selection in sugarcane

The current demand for clean and renewable energy has provoked considerable changes in the production system of agroindustrial companies. The generation of bioelectricity through the burning of sugarcane bagasse has considerably risen in the recent years. This work aimed to focus on the sugarcane genotypes selection for fiber productivity. The experiment was outlined in randomized blocks with four repetitions, and sixteen genotypes were evaluated. The evaluated traits were: cane tons per hectare, sucrose tons per hectare, fiber tons per hectare, fiber content and apparent sucrose content. To the selection, the mixed linear models methodology was used. The heritability coefficients suggest a significant genetic gain and the harmonic means of relative performances of predicted genotypic values allowed the identification of stable genotypes related to the traits evaluated in four harvest cycles. Considering the current average demand of sugarcane agroindustry for varieties with fiber content between 12% and 17% and sucrose content near 13%, for energy generation and sugar production, the genotypes EECAC 06, EECAC 03, EECAC 04 and EECAC 07 are presented as commercial cultivation options. Highlights - Mixed models constitute an efficient tool for sugarcane selection focused onto fiber and sucrose production. - This methodology provides significant genetic gains based on predicted genetic values free from interaction with harvest cycles. - The evaluated genotypes present high fiber and sucrose productivity, genotypic adaptability and stability throughout harvest cycles, indicating longevity in the sugarcane crop.

Investigation of soil nutrients and associated rhizobacterial communities in different sugarcane genotypes in relation to sugar content

Background Plant microbiomes and soil are bridged by rhizobacteria, maintaining and improving plant health and growth in different aspects. This study was conducted in the field station of the Guangxi University, Fusui, China. We investigated soil nutrients, root morphology and rhizosphere bacterial composition, and community structures in 18 sugarcane genotypes concerning sugar content under the same environmental condition. Results Most of the rhizosphere microbiomes of these genotypes exhibited similar bacterial compositions. However, the evaluated genotypes harbored a significant effect and difference in the abundance of operational taxonomic units and bacterial composition in the rhizosphere compartments. Alpha diversity analysis on the rhizosphere microbiome showed a significant difference in the bacterial diversity (Shannon index, p < 0.001) and OTU richness (Chao1, p < 0.001). The principal coordinate analysis (PCoA) and hierarchical cluster analysis revealed that the genotype replicated samples grouped, indicating their similarity. Besides, these genotypes also differed significantly in terms of root structure and soil properties. A significant genotypic effect (p < 0.05) was found in the root traits except for rooting depth. The soil chemical properties were significantly different among the evaluated genotypes. Furthermore, sucrose content was strongly correlated with the total root length (TRL) and rooting depth. Genotypes (FN-1702, GUC-3, ZZ-13, ZZ-10, ZZ-6) were the best performing and distinct in bacterial diversity, root structure, soil parameters and sucrose content. Conclusion The results showed a closely related and highly conserved bacterial community of the rhizosphere microbiome. The rhizosphere microbiome diversity and related bacterial communities were highly associated with the relevant plant taxa, probably at the order level. As a result, it is possible to conclude that the host genotype and the same environmental condition influenced the rhizosphere microbiome via root phenes. Future research regarding plant phenes and microbiome functional groups could be considered an essential factor. Graphic abstract

Honey sugars profile of stingless bee Tetragonula laeviceps (Hymenoptera: Meliponinae)

Agus A, Agussalim, Sahlan M, Sabir A. 2021. Honey sugars profile of stingless bee Tetragonula laeviceps (Hymenoptera: Meliponinae). Biodiversitas 22: 5205-5210. Honey was a functional food to improve human health, but irresponsible people used this circumstance to make fake honey. This study aimed to evaluate the profile of the sugar of stingless bee honey [Tetragonula laeviceps (Smith, 1857)] from different geographical origins in Indonesia. Honey, three samples were directly collected from three other sources for meliponiculture of T. laeviceps in Indonesia: Sleman, Klaten, and Gunungkidul. The honey sugars profile was analyzed: glucose, fructose, sucrose, reducing sugar, the sum of fructose and glucose, glucose to moisture ratio, fructose to glucose ratio, and honey pH. Glucose and fructose were analyzed by HPLC, sucrose by Luff Schoorl, reducing the sugar by Layne-Enyon, and pH by a pH meter. The current findings revealed that the geographical origins had a highly significant effect on glucose, fructose, the sum of fructose and glucose, glucose to moisture ratio, fructose to glucose ratio, and honey pH (P<0.01) and significant effect on reducing sugar (P<0.05), but not on sucrose content. Thus, it can be concluded that the origins were affecting the honey sugars profile and honey from Sleman has the highest sugars content, followed by honey from Klaten and the lower was honey from Gunungkidul.

Foliar herbivory increases sucrose concentration in bracteal extrafloral nectar of cotton

Cultivated cotton, such as Gossypium hirsutum L., produces extrafloral (EF) nectar on leaves (foliar) and reproductive structures (bracteal) as an indirect anti-herbivore defense. In exchange for this carbohydrate-rich substance, predatory insects such as ants protect the plant against herbivorous insects. Some EF nectar-bearing plants respond to herbivory by increasing EF nectar production. For instance, herbivore-free G. hirsutum produces more bracteal than foliar EF nectar, but increases its foliar EF nectar production in response to herbivory. This study is the first to test for systemically induced changes to the carbohydrate composition of bracteal EF nectar in response to foliar herbivory on G. hirsutum. We found that foliar herbivory significantly increased the sucrose content of bracteal EF nectar while glucose and fructose remained unchanged. Sucrose content is known to influence ant foraging behavior and previous studies of an herbivore-induced increase to EF nectar caloric content found that it led to increased ant activity on the plant. As a follow-up to our finding, ant recruitment to mock EF nectar solutions that varied in sucrose content was tested in the field. The ants did not exhibit any preference for either solution, potentially because sucrose is a minor carbohydrate component in G. hirsutum EF nectar: total sugar content was not significantly affected by the increase in sucrose. Nonetheless, our findings raise new questions about cotton’s inducible EF nectar responses to herbivory. Further research is needed to determine whether an herbivore-induced increase in sucrose content is typical of Gossypium spp., and whether it constitutes a corollary of systemic sucrose induction, or a potentially adaptive mechanism which enhances ant attraction to the plant

Lemon maturation causes anatomical and biochemical changes at the flavedo tissue level

Plants mobilize the photosynthates by three transport pathways: apoplastic, symplastic through plasmodesmata (PD), and transcellular. In flavedo of postharvest mature lemons, a high activity of cell wall-bound invertase (WI), an enzyme associated with transcellular transport of monosaccharides, has been detected. In order to elucidate whether this high enzymatic activity is related to restricted transport in the symplastic pathway with fruit maturation, the aim of the present work was to compare anatomical and biochemical parameters in peel tissues of immature and mature lemons. Anatomical structure focusing on cell walls, callose deposition, WI activity, and sucrose content were analyzed in peel tissues of immature and mature lemons. The parenchyma of flavedo tissue of immature lemons presented an elevated number of primary pit fields (PPF). These PPF, associated to PD or cell wall interruptions, had the appearance of a string of beads. However, in mature lemons, the number of PPF was scarce due to callose deposition. WI activity and apoplastic sucrose content increased significantly in flavedo of mature lemons in comparison to immature lemons. Present findings lay structural and functional bases relevant to understand differences between immature and mature lemons, which would help to design agricultural practices in pre- and post-harvest management.

Analysis of Phenotypic Characteristics and Sucrose Metabolism in the Roots of Raphanus sativus L.

The taproot of radish (Raphanus sativus L.) is an important sink organ; it is morphologically diverse and contains large amounts of secondary metabolites. Sucrose metabolism is believed to be important in the development of sink organs. We measured the amounts of glucose, fructose, and sucrose in the roots of sixty three radish accessions and analyzed the association between the sugar content and the root phenotype. Fructose content correlated with the root color and length characteristics, glucose was the most abundant sugar in the roots, and the sucrose content was very low, compared to that of the hexoses in most of the accessions. Expression analysis of the genes involved in sucrose metabolism, transportation, starch synthesis, and cell wall synthesis was performed through RNA sequencing. The genes encoding sucrose synthases (SUSY) and the enzymes involved in the synthesis of cellulose were highly expressed, indicating that SUSY is involved in cell wall synthesis in radish roots. The positive correlation coefficient (R) between the sucrose content and the expression of cell wall invertase and sugar transporter proteins suggest that hexose accumulation could occur through the apoplastic pathway in radish roots. A positive R score was also obtained when comparing the expression of genes encoding SUSY and fructokinase (FK), suggesting that the fructose produced by SUSY is mostly phosphorylated by FK. In addition, we concluded that sucrose was the most metabolized sugar in radish roots.

Influence of exopolysaccharides on viscosity of sugar juices with low sucrose contents

The presence of dextran originating from frost-damaged or degraded beet is highly detrimental during beet sugar manufacture, because they cause difficulties in filtering the carbonatation juice. In this paper the impact of exopolysaccharides on the viscosity of low sucrose content juices including: raw juice, juice after the 1st filtration and thin juice were analyzed. Studies have shown that high molecular mass exopolysaccharides have a stronger effect on the juice viscosity than low molecular mass exopolysaccharides. However, the dynamic viscosity of technical sugar solutions (raw juice or thin juice) with exopolysaccharides at a content of up to 0.5 g/kg, is lower than the viscosity of pure sugar solutions having the same refractometric dry substance content (RDS).