Compositions, taste characteristics, volatile profiles, and antioxidant activities of sweet sorghum (Sorghum bicolor L.) and sugarcane (Saccharum officinarum L.) syrups

Sweet sorghum juice clarification and concentration: a review

Sweet sorghum is a promising biomaterial, considering its nutritional and energy value, unpretentiousness in cultivation and its promising economic parameters of processing. The concentrate of sweet sorghum juice is an outstanding material for food purposes, meeting the emerging trends of the industry. This review presents data on the physicochemical properties of sweet sorghum juice and sirup, as well as technological details on the processes of its pretreatment, clarification, and concentration. Physicochemical properties of raw juice of sweet sorghum, as well as purified juice and sirup, are discussed in terms of material pretreatment, methods of clarification and concentration, and storage conditions. Comprehensive theoretical principles, methodological details and explanations of the consistency of sweet sorghum juice processing are given. This work focuses entirely on the relationship between sweet sorghum juice treatment methods and its composition and provides versatile source of information for food science community, farmers, and entrepreneurs.

Study on the effect of Cr(VI) removal by stimulating indigenous microorganisms using molasses

Molasses have a prominent effect on the bioremediation of Cr(VI) contaminated groundwater. However, its reaction mechanism is not detailed. In this paper, the removal of Cr(VI) with different carbon sources was compared to explore the effect and mechanism of the molasses. The addition of molasses can completely remove 25 mg/L Cr(VI), while the removal efficiency by glucose or emulsified vegetable oil was only 20%. Molasses could rapidly stimulate the reduction of Cr(VI) by indigenous microorganisms and weakened the toxicity on bacteria. The average removal rate of Cr(VI) was 0.42 mg/L·h, 10 times that of glucose system. Compared with glucose, molasses can remediate Cr(VI) at a higher concentration (50 mg/L), and the carbohydrate acted as microbial nutrients. Direct and indirect reduction acted together, the Fe(II) content in the aquifer medium increased from 1.7% to 4.7%. The addition of molasses extract into glucose system could increased the removal rate of Cr(VI) by 2-3 times, and the ions of molasses had no significant effect on the reduction. Excitation emission matrix fluorescence spectra and electrochemical analysis proved that the molasses contained humic acid-like substances, which had the ability of electron shuttle and improved the reduction rate of Cr(VI). In the process of bioreduction, the composition of molasses changed and the electron transport capacity increased from 104.2 to 446.5 μmol/(g C), but these substances could not be used as electron transport media to continuously enhance the reduction effect. This study is of great significance to fully understand the role and application of molasses.

Silage Mixtures of Alfalfa with Sweet Sorghum Alter Blood and Rumen Physiological Status and Rumen Microbiota of Karakul Lambs

The study investigated the effects of feeding mixtures of alfalfa (AF) and sweet sorghum (SS) at different ratios of silages in terms of the physiological status of blood and rumen, and rumen microbiota in lambs. A total of 30 four-month-old male Karakul lambs with 25.5 ± 1.4 kg mean initial body weight were randomly allocated to five groups, with six lambs in each group. Five experimental diets containing 40% of one of the five AF−SS mixed silages (containing 0%, 20%, 40%, 60%, and 80% AF on a fresh weight basis, respectively) and 60% of other ingredients were formulated. Overall, the results showed that the mixed silage with more AF tended to increase serum antioxidant capacity, dry matter (DM) intake, and rumen fermentation metabolites. The AF−SS mixed silages containing AF at 60% and 80% caused a significant linear increase (p < 0.05) in the activity of total antioxidant capacity. The superoxide dismutase in the Karakul lamb responded with significant linear and quadratic increases (p < 0.01) as the ratio of AF was increased in the AF−SS mixed silages. Feeding diets with AF in silage mixtures at the ratio of 60% significantly increased (p < 0.05) the concentration of ruminal total volatile fatty acids (tVFA), acetate, and ammonia-N. However, no statistical significance (p > 0.05) was found in the alpha diversity of rumen microbes among the tested groups (p > 0.05). Principal coordinates analysis could clearly discriminate the differences between the five groups (p = 0.001). The relative abundance of Firmicutes in the rumen were significantly higher with AF at 40% in the AF−SS silage-based diet than those with AF at 0%, and 20% ratios. The abundance of Ruminococcus_albus had a significant linear increase (p < 0.05), as the ratio of AF in the AF−SS mixed silages was increased. In conclusion, the best beneficial effect on the physiological status of the blood and rumen, DM intake, and rumen microbiota in lambs came from those that consumed the diet containing the AF−SS mixed silage with 60% AF.

MicroSugar: A database of comprehensive miRNA target prediction framework for sugarcane (Saccharum officinarum L.)

microRNA (miRNA) is a group of small non-coding RNA that plays important role in post-transcription of gene expression. With the studies about miRNA increase in sugarcane, the researchers lack an exhaustive resource to achieve the data. To fill this gap, we developed MicroSugar, a database that supported mRNA and miRNA annotation for sugarcane (http://suc.gene-db.com). MicroSugar is an integrated resource developed for 194,528 genes including 80,746 unigenes from long reads of Pacbio platform and 468 miRNAs from 72 samples. Internode elongation (jointing) is the key biological characteristic for the growth of sugarcane tillers into sugarcane stems. The present study combined the sequencing data from the different stages in internode elongation of stem and tiller. In total, the 14,300 3' untranslated region (UTR) sequences were extracted from the gene sequences and 3019 mRNAs as target of 327 miRNA were identified by miRanda algorithm and Spearman's Rho of expression levels. To determine the gene functions regulated by these miRNAs, the gene ontology enrichment analysis was performed and it confirmed that the over-represented Gene Ontology (GO) terms were associated with organism formation indicating the growth controlling function by miRNAs in sugarcane. Moreover, MicroSugar is a comprehensive and integrated database with a user-friendly responsive template. By browsing, searching and downloading of the nucleotide sequences, expression and miRNA targets, the user can retrieve information promptly. The database provides a valuable resource to facilitate the understanding of miRNA in sugarcane development and growth which will contribute to the study of sugarcane and other plants.

Natural sweeteners: Sources, extraction and current uses in foods and food industries

Food producers have leaned towards alternative natural and synthetic sweeteners in food formulations to satisfy market demands. Even so, several synthetic sweeteners (e.g., aspartame, saccharin, sucralose) are becoming less popular due to health-related concerns, lower nutritional values, and controversies around their safety. Conversely, natural sweeteners confer favourable customer perceptions due to their association to a healthier lifestyle and higher nutritional values. This article discusses the evidence of natural sweeteners in the available commercial products. A comprehensive review of natural sweeteners is presented, which includes their resources, properties and extraction methods, as well as a discussion on several emerging technologies that offer improvements to the traditional extraction methods. Finally, the progress of natural sweeteners in the food industry is assessed, and the commercial food products containing these natural sweeteners are mentioned.

A Predictive Strategy Based on Volatile Profile and Chemometric Analysis for Traceability and Authenticity of Sugarcane Honey on the Global Market

Sugarcane honey (SCH) is a syrup produced on Madeira Island and recognized by its unique aroma, a complex attribute of quality with an important influence on the final consumer's acceptance of the product, and determined by a complex mixture of a large number of volatile organic compounds (VOCs) generated during its traditional making process and storage. Therefore, the purpose of this study was to establish the volatile profile of genuine SCH produced by a regional certified producer for seven years and compare it with syrups from non-certified regional producers and with producers from different geographical regions (Spain, Egypt, Brazil and Australia), as a powerful strategy to define the volatomic fingerprint of SCH. Different volatile profiles were recognized for all samples, with 166 VOCs being identified belonging to different chemical classes, including furans, ketones, carboxylic acids, aldehydes and alcohols. Chemometric analysis allowed (i) the differentiation between all syrups, being more pronounced between SCH and other syrups; and (ii) the identification of 32 VOCs as potential markers for the traceability and authenticity of SCH on the global market.

Formation of Volatile and Aroma Compounds during the Dehydration of Membrane-Clarified Sugarcane Juice to Non-Centrifugal Sugar

The development of volatile compounds and their precursors during the dehydration process of membrane-clarified sugarcane juice to non-centrifugal sugar (NCS) was investigated. Head-space solid phase microextraction/gas chromatography–mass spectrometry (HS-SPME/GC–MS) coupled with chemometrics was employed to assess the differences at the various stages of the dehydration process. A total of 111 volatile compounds were identified, among which 57 were endogenous compounds from sugarcane juice and displayed an attenuated abundance in the first 30 min. Typical oxygen and nitrogen heterocyclic compounds, including furans and pyrazines, and aldehydes derived were found to be the main volatiles contributing to the formation of NCS characteristic aroma, with phenols, alcohols, esters, acids, and sulfur compounds as supplementary odor. Free amino acids and reducing sugars were identified as important precursors for the aroma development process. The low temperature (90–108 °C) and micro vacuum condition (−0.03 MPa) approach used in this study could be an alternative option for the manufacture of NCS.

Effect of processing and storage on the volatile profile of sugarcane honey: A four-year study

Sugarcane honey (SCH) is a syrup from Madeira Island recognized by its unique and excellent aroma, associated to volatile organic compounds (VOCs) generated during the well-defined five stages of its traditional making process. The establishment of volatile profile throughout all SCH-making stages during four years, allowed the evaluation of the influence of each stage in the typical characterisitcs of SCH. One hundred eighthy seven VOCs were identified, being associated to several origins and formation pathways. VOCs formed during stage 1 and 2 were originate from raw material, and its oxidation (i.e. enzymatic browning) and thermal degradation (i.e. lipid oxidation, Maillard reactions, Strecker degradation). In stage 3 and 4, the caramelization and melanoidin degradation also occurred, while in stage 5, the thermal degradation continues, followed by microbial activity. Chemometric analysis allowed to identify 35 VOCs as potential markers for processing control by the producers and as guarantee of the typicality and authenticity of SCH. Based on the obtained results, we propose for the first time an innovative schematic diagram explaining the potential reactions and pathways for VOCs formation during the different steps of the SCH production.

Phenolic contents, antioxidant potential and associated colour in sweet sorghum syrups compared to other commercial syrup sweeteners

BACKGROUND

Knowledge of the bioactive content of sweet sorghum syrups compared to other common food-grade syrups will expand their utilisation as a food source. Total phenolic content (TPC), phenolics evaluated by high-performance liquid chromatography, antioxidant 2,2-diphenyl-1-picryl hydrazyl (DPPH) radical scavenging activities and oxygen radical absorbance capacity (ORAC), as well as colour of high-fructose corn syrup (HFCS), corn, honey, maple, agave, rice and grain sorghum syrups, were compared to 10 commercial sweet sorghum syrups.

RESULTS

Sweet sorghum syrups contained markedly higher (P ≤ 0.05) TPC (6471 ± 1823 mg L^-1 ) compared to the other syrups (596 ± 497 mg L^-1 ). HFCS, corn, white grain sorghum and rice syrups had negligible and low DPPH radical scavenging activities and ORAC values, respectively. DPPH activities, ORAC and colour values of the sweet sorghum syrups were also markedly (P ≤ 0.05) higher than other syrups and highly related. The predominant phenolic components identified in sweet sorghum syrups were phenolic acids. Ellagic acid and protocatechuic acid were found in sorghum syrups ranging in concentration from 335-1177 and 53-485 μg g^-1 , respectively. Sinapic acid was detected in several sorghum syrups, ranging in concentrations between 21 and 3654 μg g^-1 .

CONCLUSION

HFCS, corn, white grain sorghum and rice syrups demonstrated low bioactivity with negligible and low DPPH activities and ORAC values, respectively. The TPC, DPPH, ORAC and colour values of the sweet sorghum syrups were related to each other and markedly (P ≤ 0.05) higher compared to the other syrups. Phenolic acids were the predominant phenolic compounds identified in sorghum syrups and represent potential for health benefits. Published 2020. This article is a U.S. Government work and is in the public domain in the USA.

Removal of color and turbidity in sugarcane juice treated by electrocoagulation with aluminum electrodes

Abstract The liming (Ca(OH)2 addition) and sulfitation (HSO3- addition) is the conventional treatment for purification of sugarcane juice (SCJ) in sugar cane mills to crystal sugar production. Although, the sulfite has been associated to human health problems, this industrial step kept untouchable or few studies have been made to change this scenery. This work aimed to evaluate the variables which influence the electrocoagulation performance on the SCJ purification as a sulfur-free crystal sugar process. A fractional factorial design with the surface response methodology was used to evaluate the influence of voltage, pH, soluble solids total (Brix), temperature and distance between the electrodes in the electrocoagulation process. The outputs were turbidity, juice color, sucrose contents (as pol%juice) and Reducing Sugars (RS). Residual aluminum was analyzed by voltammetry to control de aluminum releasing into the treated juice. The electrocoagulation reduced color and turbidity, in special at low pH (2.5), highest voltage (25 V) and minimal distance of electrode (1.0 cm). Although in this conditions, sucrose was converted into RS indicating partial hydrolysis. In this work, the most part of residual aluminum went to floated and precipitated phases (76.8% and 18.1%, respectively), whereas only 5.1% remained in the SCJ clarified. Electrocoagulation/electroflotation proved to be a potential technique as a substitute for sulfitation in SJC treatment, which ensures the production of safe food for humans.

Advanced GC-MS method for quality and safety control of alcoholic products

Recently developed and validated simple and reliable quantitative method employing ethanol as an internal standard (IS) for GC-MS quantification of volatile compounds in alcoholic products was applied to 36 samples including commercially available world-famous brand spirits from 18 countries and homemade distillates. The GC-MS analyses were performed simultaneously by the suggested approach and official IS method that is prescribed in the legislation of EU and USA. The independent samples t-test was employed to evaluate the statistical difference between the results of these two methods. The test revealed no difference in the results and their repeatability. The main benefits of the suggested method are the elimination of the necessity of manual IS addition and samples density measurement thus making it more economical and productive.

Effects of liming on the flavor of kokuto-shochu, a spirit made from non-centrifugal sugar

Kokuto-shochu is a traditional Japanese spirit prepared from kokuto, a non-centrifugal brown cane sugar. When manufacturing kokuto, lime is added to the sugarcane juice to accelerate the crystallization of sucrose. Although the liming process differs depending on the manufacturer, the effects of liming on the quality of kokuto-shochu are unclear. Therefore, we investigated the flavor characteristics and volatiles present in kokuto-shochu prepared from kokuto with different liming degrees. Kokuto-shochu prepared from kokuto without liming had a pronounced kokuto-like flavor with a rich taste and contained higher contents of nerolidol, nonanal, acetoin, β-damascenone, and 4-hydroxy-2,5-dimethyl-3(2H)-furanone compared to that prepared from kokuto with liming. On the other hand, kokuto-shochu prepared from kokuto with excess liming had a comparative grassy flavor. It contained higher esters, 4-vinylguaiacol, and pyrazines compared to other shochu. The levels nerolidol, isoamyl acetate, nonanal, and acetoin were affected by the mash pH during fermentation, and thus, liming would affect the formation of such volatiles via changing the mash pH. In contrast, pyrazines, 4-vinylguaiacol, and 4-hydroxy-2,5-dimethyl-3(2H)-furanone were not affected by mash pH, and their levels in the kokuto-shochu were consistent with those in kokuto raw materials. These results suggested that the liming process affects the levels of volatiles in kokuto-shochu by changing the mash pH and volatile levels in kokuto raw materials.

Comparative Analysis of In Vitro Responses and Regeneration between Diverse Bioenergy Sorghum Genotypes

Sorghum has been considered a recalcitrant plant in vitro and suffers from a lack of regeneration protocols that function broadly and efficiently across a range of genotypes. This study was initiated to identify differential genotype-in vitro protocol responses across a range of bioenergy sorghum parental lines and the common grain sorghum genotype Tx430 in order to characterize response profiles for use in future genetic studies. Two different in vitro protocols, LG and WU, were used for comparisons. Distinct genotype-protocol responses were observed, and the WU protocol performed significantly better for plantlet regeneration. Most bioenergy genotypes performed as well, if not better than Tx430, with Rio and PI329311 as the top regenerating lines. Genotypes displayed protocol-dependent, differential phenolic exudation responses, as indicated by medium browning. During the callus induction phase, genotypes prone to medium browning exhibited a response on WU medium which was either equal or greater than on LG medium. Genotype- and protocol-dependent albino plantlet regeneration was also noted, with three of the bioenergy genotypes showing albino plantlet regeneration. Grassl, Rio and Pink Kafir were susceptible to albino plantlet regeneration, with the response strongly associated with the WU protocol. These bioenergy parental genotypes, and their differential responses under two in vitro protocols, provide tools to further explore and assess the role of genetic loci, candidate genes, and allelic variants in the regulation of in vitro responsiveness in sorghum.