Antioxidant activity in sugarcane juice and its protective role against radiation induced DNA damage

Determining the impact of pre-pressing pretreatments applied to sugarcane on the aroma compounds and quality characteristics of sugarcane juice

The study examined the effects of three pretreatments, blanching (5, 10, and 30 min), ultrasound (15, 20, and 30 min), and steam blanching (10, 20, and 30 min) on sugarcane, assessing their impact on sugarcane juice quality parameters and aroma compounds. The control had the highest soluble solid content, while the ultrasound-15 min (US-15 min)-treated sample had the lowest, affecting pH, total acidity, and color values significantly. Color analysis showed lower L* values and less greenish tones in treated samples. The implemented pretreatments effectively reduce the browning index, with the US-20 min treatment showing the most significant reduction compared to the control sample. All pretreatments deactivated polyphenol oxidase. Carbon isotope analysis yielded significant results. Principal component analysis and hierarchical clustering linked 1,1-diphenyl-2-picrylhydrazyl (DPPH) with 2,2'-azino-bis 3-ethylbenzothiazoline-6-sulfonic acid (ABTS) and 5-hydroxymethyl furfural (HMF) with total phenolic content. The study also highlights significant variations in aroma compound profiles among pretreated sugarcane juice samples, with blanching for 10 min showing notable increases in specific compounds like 2-heptanone and nonanol. Hierarchical clustering showed similarities between blanching-30 min and US-30 min, contrasting with the control. Blanching-10 min had a positive impact on sugarcane juice quality. In conclusion, the study emphasized how pretreatments affect physicochemical properties and aroma compounds in sugarcane juice. PRACTICAL APPLICATION: The research findings suggest that blanching and ultrasound pretreatments can be used by the food industry to improve sugarcane juice quality by reducing browning, enhancing color, and altering aroma profiles. These pretreatments could extend the shelf life and appeal of sugarcane juice, making it more attractive to consumers while maintaining its nutritional properties.

Bioactive compounds as an alternative for the sugarcane industry: Towards an integrative approach

Here, a comprehensive review of sugarcane industrialization and its relationship with bioactive compounds (BCs) detected in various products and by-products generated during its processing is presented. Furthermore, it is discussed how these compounds have revealed important antioxidant, antineoplastic, antidiabetic, and antimicrobial activities. From this bibliographic research highlights the significance of two types of BCs of natural origin (phenolic compounds (PCs) and terpenoids) and a group of compounds synthesized during industrial transformation processes (Maillard reaction products (MRPs)). It was found that most of the studies about the BCs from sugarcane have been conducted by identifying, isolating, and analyzing ones or a few compounds at a specific period, this being a conventional approach. However, given the complexity of the synthesis processes of all these BCs and the biological activities they can manifest in a specific biological context, novel approaches are needed to address these analyses holistically. To overcome this challenge, integrating massive and multiscale methods, such as omics sciences, seems necessary to enrich these studies. This work is intended to contribute to the state of the art that could support future research about the exploration, characterization, or evaluation of different bioactive molecules from sugarcane and its derivatives.

TRIM59 promotes steatosis and ferroptosis in non-alcoholic fatty liver disease via enhancing GPX4 ubiquitination

Non-alcoholic fatty liver disease (NAFLD) is the most common liver disease around the world. However, no specific medicine has been approved for NAFLD treatment. Our study was conducted to explore the role and mechanism of TRIM59 in NAFLD, aiming to provide a novel target for NAFLD treatment. Here, the expression of TRIM family members was detected in 10 mild and severe NAFLD tissues as well as 10 normal tissues. TRIM59 expression was verified in 10 normal tissues and 25 mild and severe NAFLD tissues. Palmitic acid and high-fatty diet were used for the construction of NAFLD models. Oil Red O staining was used to detect the level of steatosis. The content of TNF-α, IL-6, and IL-8 was measured to reflect the level of inflammation. Lipid reactive oxygen species was estimated by flow cytometry. We found that TRIM59 was highly expressed in NAFLD tissues compared with normal liver tissues. The inhibition of TRIM59 could inhibit the steatosis and inflammation in NAFLD, whereas its overexpression exhibited reversed effects. The application of ferroptosis inhibitor, deferoxamine, could markedly ameliorate steatosis and inflammation, which was mediated by overexpressed TRIM59. Besides, TRIM59 was demonstrated to interact with GPX4 and promoted its ubiquitination. The overexpression of GPX4 could significantly reverse the pathogenic effects of TRIM59 in NAFLD. Additionally, the inhibition of TRIM59 appeared to be a promising strategy to ameliorate NAFLD in mice model. In summary, our study revealed that TRIM59 could promote steatosis and ferroptosis in NAFLD via enhancing GPX4 ubiquitination. TRIM59 could be a potential target for NAFLD treatment.

Sugarcane Straw Polyphenols as Potential Food and Nutraceutical Ingredient

The sugarcane processing industry generates a large amount of straw, which has a negative environmental impact, and high costs are associated with their elimination, wasting their potential bioactive value attributed to their richness in polyphenols. In this study, an ethanolic extract produced from sugarcane straw was screened for its phenolic compounds content, and the potential use of this extract in the development of a food ingredient was further evaluated. Fifty different secondary metabolites belonging to the hydroxybenzoic acids, hydroxycinnamic acids, and flavonoids were identified by liquid chromatography-electrospray ionization-ultrahigh-resolution-quadrupole time of flight-mass spectrometry (LC-ESI-UHR-QqTOF-MS). The predominant phenolic compounds found were 4-hydroxybenzaldehyde, chlorogenic acid, and 5-O-feruloylquinic acid. The obtained extracts showed strong potential as food preservatives by exhibiting (a) antioxidant activity using both 2.2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt radical cation (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) methods; and (b) antimicrobial capacity, with a minimum inhibitory concentration of 50 mg/mL for Staphylococcus aureus, 74% inhibition for Bacillus cereus, and 44% for Salmonella enterica; and (c) the capacity to inhibit a food browning enzyme, tyrosinase (28-73% for 1-8 mg/ mL). Moreover, the extracts showed antidiabetic potential by inhibiting the enzymes α-glucosidase (15-38% for 1.25-5.00 mg/mL) and dipeptidyl peptidase-IV (DPP-IV) (62-114% for 0.31-5.00 mg/mL). The extract (0.625 mg/mL) also exhibited the capacity to reduce proinflammatory mediators (i.e., interleukins 6 and 8, and tumor necrosis factor alpha) when Caco-2 cells were stimulated with interleukin 1 beta. Thus, sugarcane straw extract, which is rich in phenolic compounds, showed high potential to be used in the development of food-preservative ingredients owing to its antioxidant and antimicrobial potential, and to be explored as a food supplement in diabetes prevention and as coadjuvant to reduce intestinal inflammation by reducing proinflammatory mediators.

Replacement of refined sugar by natural sweeteners: focus on potential health benefits

Refined sugar is a processed product containing 99% sucrose, which is obtained from sugarcane (70%) or sugar beet (30%). In modern societies, sugar continues to play a significant role in the diet, recognised not only for its flavour and special sweetening properties but also for its role in food preservation. On the other hand, a high consumption of refined sugar is associated with non-communicable diseases and many health issues such as a high risk of dental caries, overweight and neurodevelopmental disorders in children. Alternatives like unrefined sugars have generated a lot of interest as a healthy substitute due to their nutraceutical properties. This paper is aimed to review the beneficial effects of sugar derived from natural sources and highlight health problems that could be caused by refined processed sugar. Refined sugar is frequently used in variety of items including processed foods, soft drinks or ice creams although it is considered unhealthy due to its high salt and sugar content as well as added fats and artificial coloring. Natural sugars are preferred because they have a high nutritional value and a high concentration of healthy compounds, which offset the negative effects of refined sugar. Therefore, removing refined sugar or at least reducing its consumption should be promoted as a healthier option in food choices.

Coloration mechanisms of fresh sugarcane juice: Investigating the critical components and enzyme activity

The color of sugarcane juice has a great influence on the preferences of consumers. The contents of pigments, sugars, free amino acids, organic acids, phenolic compounds, enzyme activities, antioxidant activities, and color differences among juices produced from four sugarcane varieties were investigated in this study. The data suggested that variety played an important role in the color and chemicophysical properties of sugarcane juice. The color of four varieties of sugarcane juice varied from greenish yellow to light brown. Bamboo cane juice and black rind sugarcane juice presented similar color properties and both had high contents of phenolic compounds and strong antioxidant activities. Yellow rind sugarcane juice with higher value of L* (26.10) and more pigment contents than the other varieties was attractive. Sucrose, glucose, β-alanine, chlorogenic acid, p-hydroxybenzoic acid, isochlorogenic acid, DPPH, and polyphenol oxidase activity had positive correlations with a* value. The effects of organic acids on color were limited. PRACTICAL APPLICATION: This study demonstrated the relationships between color parameters and contents of pigments, sugars, free amino acids, organic acids, phenolics, enzyme activities, and antioxidant activities of sugarcane juice. This could help to find out the coloration mechanisms of sugarcane juice. Our manuscript created a paradigm for future studies on color control during juice processing and storage.

Antioxidant activity, nutritional and physicochemical characteristics, and toxicity of minimally refined brown sugar and other sugars

Minimally refined brown sugar (MRBS) is a brown sugar derived from sugarcane that has a low glycemic index. This study aimed to determine and compare the antioxidant contents and nutritional and physicochemical properties of MRBS, refined sugar (RS), and brown sugar (BS). In addition, the toxicity of these sugars was evaluated via in vitro cytotoxicity method and by using a zebrafish model. Results showed that MRBS was better than the two other sugars because it has a lower moisture content and higher ash content. The contents of potassium and manganese of MRBS were higher than those of the two other sugars. Surprisingly, MRBS also contained selenium, which was not detected in RS and BS. The major phenolics in MRBS are 4-hydroxybenzoic acid, chlorogenic acid, protocatechuic acid, trans-Ferulic acid, and apigenin. All sugar solutions and their antioxidant-containing extracts were not cytotoxic to 3T3-L1 adipocytes.

Saccharum officinarum juice alters reproductive functions in male Wistar rats

Infertility is a problem across almost all cultures and societies. Problems in the male partner, especially as a result of unhealthy dietary habits, are the commonest single group of course. Many populations, therefore, tend more toward the use of natural dietary substitutes opined to proffer less risk to reproductive functions and more health benefits. Saccharum officinarum juice (SOJ) is a widely consumed, energy-rich, nutritious substance that has many minerals and enzymes. Saccharum officinarum plant was reported to have anti-thrombosis, anti-inflammatory and immune-stimulatory activities. This study evaluated the reproductive effects of S. officinarum juice in male Wistar rats. A sugarcane press juicer was used to extract S. officinarum juice. Twenty male Wistar rats (100-120 g) grouped into four (n = 5) received 1.0 mL/kg/day distilled water (control), and 1.0, 3.2 and 10.0 mL/kg/day of fresh S. officinarum juice once daily for 8 weeks via gavage. Sperm analysis, histology of testes and epididymides were evaluated by microscopy. Enzyme-linked immunosorbent assay (ELISA) was used in assessing the serum levels of luteinizing hormone, follicle-stimulating hormone and testosterone. Data were analyzed using the analysis of variance at a significance of p < 0.05. SOJ increased fasting blood glucose levels in 3.2 and 10.0 mL/kg groups. The 10.0 mL/kg juice caused a significant increase in testosterone level and sperm count, and it also increased the percentage of aberrant sperm and decreased sperm viability. Saccharum officinarum juice impaired the histological integrity of the testes and epididymides. Thus, S. officinarum juice adversely altered the reproductive functions of male Wistar rats by reducing sperm quality and disrupting testicular architecture.

Ghazali H, Chang LS, Manaf YN. Coconut (Cocos nucifera L.) sap as a potential source of sugar: Antioxidant and nutritional properties

This study was carried out to compare the antioxidant and nutritional properties of coconut (Cocos nucifera L.) sap with other natural sources of sugar such as sugar palm (Borassus flabellifer) and sugarcane (Saccharum officinarum L.). Coconut sap and juice from sugar palm and sugarcane were analyzed for proximate composition, pH and total soluble solid (TSS), color, sugar profile, vitamin profile, antioxidant properties (total phenolic contents, DPPH, FRAP, and ABTS), and mineral content. The results indicated that coconut sap possesses high DPPH (23.42%), FRAP (2.09 mM/ml), and ABTS (21.85%) compared with the juices. Coconut sap also had high vitamin C (116.19 µg/ml) and ash (0.27%) contents, especially in potassium (960.87 mg/L) and sodium (183.21 mg/L) which also indicating high content of minerals. These properties showed that coconut sap could be served as a potential healthier sugar source compared with sugar palm and sugarcane juices.

Antioxidant activity and polyphenol composition of sugarcane molasses extract

The antioxidant activity of sugarcane molasses ethanol extract (ME) and its fraction (ME-RBF) was evaluated using ABTS, ORAC 6.0 and CAA assays and ME-RBF demonstrated 26-fold, 12-fold and 2-fold higher values, respectively than ME. Likewise, total polyphenol and flavonoid concentration in ME-RBF are more than 10-fold higher than ME, that suggested antioxidant activity is correlated with polyphenol composition. Quantitative analysis of 13 polyphenols (chlorogenic acid, caffeic acid, sinapic acid, syringic acid, vanillin, homoorientin, orientin, vitexin, swertisin, diosmin, apigenin, tricin and diosmetin) was carried out by LCMS. MS/MS analysis allowed the tentative identification of seven apigenin-C-glycosides, three methoxyluteolin-C-glycosides and three tricin-O-glycosides some of which have not been reported in sugarcane before to the best of our knowledge. The results demonstrated that sugarcane molasses can be used as potential source of polyphenols that can be beneficial to health.

Kinetic modeling of high-pressure induced inactivation of polyphenol oxidase in sugarcane juice (Saccharum officinarum)

BACKGROUND

Polyphenol oxidase (PPO) is the main enzyme in sugarcane juice associated with rapid browning and degradation of organoleptic properties. High-pressure processing (HPP) (300-600 MPa) of sugarcane juice in combination with moderate temperatures (30-60 °C) for different processing times (10-25 min) has shown promising results in minimizing PPO activity while preserving the juice's freshness.

RESULTS

A maximum PPO inactivation of 98% was achieved at 600 MPa/60 °C/25 min, while the corresponding value for thermal treatment at 0.1 MPa/60 °C was only 66%. The nonlinearity in the inactivation data was well described by the Weibull distribution model with a high adjusted R² and reduced χ² values at all levels of pressure and temperature. The PPO inactivation data were fitted at shape parameter, β = 1 (log linear) and β ≠ 1. A refitted Weibull model was used to predict kinetic parameters such as the inactivation rate constants (k), activation energy (E_a ) and activation volume (V_a ), which govern PPO inactivation in HPP-treated sugarcane juice. A secondary kinetic model was formulated to predict the k values as a function of pressure (P) and temperature (T), incorporating E_a and V_a .

CONCLUSIONS

Combined high-pressure and temperature processing has been considered a reliable alternative to conventional heat treatment for inhibiting PPO activity in sugarcane juice. While the isothermal inactivation of PPO followed first-order kinetics, inclusion of high pressure resulted in a strong deviation from log linear kinetics. Identification of suitable kinetic models describing these inactivation processes is expected to aid product development and process control of high-pressure processed sugarcane juice. © 2018 Society of Chemical Industry.

Nutrient and Antioxidant Properties of Oils from Bagasses, Agricultural Residues, Medicinal Plants, and Fodders

OBJECTIVE

This study evaluated the physicochemical properties, fatty acid (FA) and phytochemical compositions, and free radical-scavenging potentials of oils from the bagasses: Costus afer stem (CA) and Saccharum officinarum stem (SB); agricultural residues; corn cobs (CC); tigernut chaff (TB); peanut hulls (GH); medicinal plants: Sphenocentrum jollyanum leaves (SJ) and Senna alata leaves (CS); and fodders: Pennisetum purpureum (PP), Panicum maximum (PM), and Chloris gayana stalks (CG).

METHOD

Oils from the samples were extracted using a mixture of n-hexane and isopropyl alcohol (3:2). The oils were analyzed for physicochemical properties using standard procedures, phytochemicals and FAs contents using gas chromatography-fluorescent ionization detection, and free radical-scavenging potentials using spectrophotometric methods of determination.

RESULTS

The bagasse and residue oils contained lower moisture contents (1.13%-2.38%) and acid values (1.89-9.20 mg/KOH/g), while the GH oil produced the least refractive indices, saponification value, and oil yield. CA oil contained 78% saturated FA, while SB oils contained 73.65% saturated FA and an abundance of lignoceric, palmitoleic, oleic, and arachidic acid. CC oil contained mostly behenic acid (19.65%), and GH oil produced 87.04% saturated FA, while TB oil produced 56% unsaturated FA. Oils from SJ, CS, PP, PM, and CG contained between 48.34% and 57.09% unsaturated FA. The phytochemical composition showed that ribalinidine and sapogenin were most abundant in PM oil, while lunamarine, kaempferol, and catechin were most abundant in SJ oil. GH oil produced the highest amounts of phytate (53.81 µg/ml) and oxalate (39.47 µg/ml). TB oil and oils from SJ and CS, especially at higher concentrations, matched the scavenging potentials of the standards used.

CONCLUSIONS

Due to the thermal stability and amount of short chain fatty acids (SFAs) of the SB, CA, CC, and GH oils, they are more suitable for non-food industrial purposes, while TB, SJ, and CS oil properties are recommendable for therapeutic purposes, especially for relief of oxidative stress.

Optimization of nutritional beverage developed from radish, sugarcane and herbal extract using response surface methodology

Purpose

Radish (Raphanus sativus) is valued for its nutritive and medicinal properties, but its juice is not palatable because of the pungent flavor. The purpose of this study is to optimize the blending process of radish juice by using sugarcane juice, herbal extract and salt concentration.

Design/methodology/approach

The statistical design provided 20 formulations; where herbal extract concentration varied from 0.5 to 2.5 per cent, sugarcane juice concentration from 20 to 50 per cent and salt concentration from 0 to 1.5 per cent.

Findings

The p = 0.05 was used to designate the statistical significance of all the responses under study. Different product formulations had total soluble solids (TSS) that ranged from 9.7 to 15.0°Brix, titratable acidity from 0.6 to 1.3%, pH from 3.3 to 4.0, reducing sugars from 0.6 to 0.8%, total sugars from 9.4 to 3.1%, total protein from 172.9 to 304.8 mg/100 ml, total phenols from 25.5 to 29.8 mg/100 ml, ascorbic acid from 10.4 to 19.8 mg/100 ml, antioxidant activity from 77.3 to 83.6% and overall acceptability from 5.6 to 7.7. Sugarcane juice concentration of 30%, herbal extract mixture and salt concentrations of 1 and 1.5%, respectively, were the optimized process conditions for the preparation of nutritional radish juice achieved with the best fit of desirability, i.e. 0.88. Cluster analysis revealed that concentration of sugarcane juice had the maximum significant effect on the quality characteristics of nutritional radish beverage as compared to the other two variables under study.

Originality/value

The developed product can help to promote the use of radish as a substrate for the beverage industry.

Comparative study of the physicochemical, nutritional, and antioxidant properties of some commercial refined and non-centrifugal sugars

Three refined and four unrefined branded commercial sugars available in Korea were investigated in terms of pH, soluble solids, moisture, ash content, turbidity, color values, microbial profile, reducing power, 2,2-diphenyl-1-picrylhydrazyl and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging activities, cellular antioxidant activity, and total phytoconstituent (i.e. phenolic, flavonoid, mineral, sucrose, glucose, and fructose) contents using standard analytical protocols such as high-performance liquid chromatography, gas chromatography-flame ionization detector/mass spectrometry, and inductively coupled plasma atomic emission spectroscopy. All tested physicochemical parameters were within the recommended standard levels. Significantly high nutritional and antioxidant properties were observed for the unrefined sugars, especially AUNO® sugar, whereas a high sucrose content was detected for the refined sugars. Hence, this study revealed that the degree of purification affects the nutritional values and antioxidant potentials of sugars. The present findings also indicate that unrefined sugars can be used as sweeteners in sugar-based cuisine to obtain nutritional and antioxidant-rich foodstuff.

Mycotoxin Contamination in Sugarcane Grass and Juice: First Report on Detection of Multiple Mycotoxins and Exposure Assessment for Aflatoxins B₁ and G₁ in Humans

This study was conducted to investigate the natural co-occurrence of multiple toxic fungal and bacterial metabolites in sugarcane grass and juice intended for human consumption in Upper Egypt. Quantification of the target analytes has been done using the "dilute and shoot" approach followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). A total number of 29 and 33 different metabolites were detected in 21 sugarcane grass and 40 juice samples, respectively, with a trend of concentrations being higher in grass than in juice. Among the regulated mycotoxins, only aflatoxin B₁ (AFB₁) and aflatoxin G₁ (AFG₁) were detected. The prevalence of AFB₁ was in 48% of grass samples and in 58% of juice with a maximum concentration of 30.6 μg/kg and 2.10 μg/kg, respectively. AFG₁ was detected in 10% of grass samples (7.76 μg/kg) and 18% of juice samples (34 μg/kg). Dietary exposure was assessed using a juice frequency questionnaire of adult inhabitants in Assiut City. The assessment revealed different levels of exposure to AFB₁ between males and females in winter and summer seasons. The estimated seasonal exposure ranged from 0.20 to 0.40 ng/kg b.w./day in winter and from 0.38 to 0.90 ng/kg b.w./day in summer.

Natural aflatoxin uptake by sugarcane (Saccharum officinaurum L.) and its persistence in jaggery

The present study focused on aflatoxin (AF) uptake by sugarcanes from contaminated soils, and its persistence in jaggery. Analysis of 25 agricultural soil samples from sugarcane growing fields revealed that 80% were found contaminated with AF ranging from 0.5 to 22 ppb and all samples harbored aflatoxigenic fungi. Forty percent of the juices extracted from sugarcane grown in contaminated soil recorded AF ranging from 1.0 to 9.5 ppb. Conversely, jaggery prepared from those samples was almost free from AF. Further, greenhouse experiment confirms the AF uptake ability of sugarcane plants. Analysis of sugarcane juice and jaggery collected from local vendor showed 21% (0.5 to 6.5 ppb) and 5.6% (0.5-1.0 ppb) of AF contamination, respectively. Aflatoxigenic Aspergillus flavus strain was evaluated for their ability to grow and produce AF on jaggery medium. At 14th day after inoculation, decreased concentration of AF was recorded in jaggery medium ranging from 0 to 120 mg jaggery/ml, above which AF was absent though the fungal growth was noted. From the results, it could be concluded that sugarcane plants have the ability to uptake AF from contaminated soil, but AF was reduced during jaggery preparation. Also, higher concentration of jaggery was inhibitory to AF production.

Impact of nano-CaCO3 -LDPE packaging on quality of fresh-cut sugarcane

BACKGROUND

In order to evaluate the effects of nano-CaCO3 -based low density polyethylene (nano-CaCO3 -LDPE) packaging on the quality of fresh-cut sugarcane, concentrations of O2 and CO2 within the packages, overall visual quality (OVQ), total bacterial count (TBC), yeast and mould count (YMC), reducing sugar content and total phenolic content, respiration, ethylene production, and the activities of phenylalanine ammonia-lyase (PAL), polyphenol oxidase (PPO), peroxidase (POD), acid invertase (AI) and neutral invertase (NI) were examined during storage at 10 °C for 5 days.

RESULTS

The transmission rate of O2 and CO2 of the nano-CaCO3 -LDPE material was lower than that of LDPE, which lead to the more rapid formation of gas environment with low O2 and high CO2 concentration in the package. TBC and YMC counts of fresh-cut sugarcane were significantly retarded by nano-CaCO3 -LDPE packaging. Nano-CaCO3 -LDPE packaging fresh-cut sugarcane exhibited significantly lower activities of PAL, PPO, POD AI and NI than LDPE packaging fresh-cut sugarcanes during the storage. Meanwhile, nano-CaCO3 -LDPE packaging significantly inhibited the increase of browning index and total phenolic content, while improving OVQ.

CONCLUSION

Our results indicated that nano-CaCO3 -LDPE packaging together with the cold storage is a promising approach in inhibiting browning and maintaining quality of fresh-cut sugarcane.

Antioxidant and nitrite-scavenging capacities of phenolic compounds from sugarcane (Saccharum officinarum L.) tops

Sugarcane tops were extracted with 50% ethanol and fractionated by petroleum ether, ethyl acetate (EtOAc), and n-butyl alcohol successively. Eight phenolic compounds in EtOAc extracts were purified through silica gel and Sephadex LH-20 column chromatographies, and then identified by nuclear magnetic resonance and electrospray ionization mass spectra. The results showed that eight phenolic compounds from EtOAc extracts were identified as caffeic acid, cis-p-hydroxycinnamic acid, quercetin, apigenin, albanin A, australone A, moracin M, and 5'-geranyl-5,7,2',4'-tetrahydroxyflavone. The antioxidant and nitrite-scavenging capacities of different solvent extracts correlated positively with their total phenolic (TP) contents. Amongst various extracts, EtOAc extracts possessed the highest TP content and presented the strongest oxygen radical absorbance capacity (ORAC), 1,1'-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging capacity, 2,2'-azobis-3-ethylbenthiaazoline-6-sulfonic acid (ABTS) radical-scavenging capacity, ferric reducing antioxidant power (FRAP) and nitrite-scavenging capacity. Thus, sugarcane tops could be promoted as a source of natural antioxidant.

Sugar cane stillage: a potential source of natural antioxidants

Biorefinery of sugar cane is the first economic activity of Reunion Island. Some sugar cane manufactured products (juice, syrup, molasses) have antioxidant activities and are sources of both phenolic compounds and Maillard Reaction Products (MRP). The study aimed to highlight the global antioxidant activity of sugar cane stillage and understand its identity. Chromatographic fractionation on Sephadex LH-20 resin allowed the recovery of a MRP-rich fraction, responsible for 58 to 66% of the global antioxidant activity according to the nature of the sugar cane stillage (DPPH test), and a phenolic compounds-rich fraction for 37 to 59% of the activity. A good correlation was recorded between the antioxidant activity of the sugar cane stillage and its content in total reducing compounds amount (Folin-Ciocalteu assay), among them 2.8 to 3.9 g/L of phenolic compounds (in 5-caffeoylquinic acid equivalent). Preliminary experiments by HPLC-DAD-MS allowed to identify several free phenolic acids and gave clues to identify esters of quinic acids.