Changes in physico-chemical, astringency, volatile compounds and antioxidant activity of fresh and concentrated cashew apple juice fermented with Lactobacillus plantarum.

Changes in physico-chemical qualities (pH, total acidity, total and reducing sugar, total phenolic and vitamin C), astringency compounds (condensed and hydrolysable tannin), antioxidant activities [2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis (3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) radical] and flavor volatile compounds in Lactobacillus plantarum-fermented cashew-apple-juice (CAJ) and 11.4 °Bx concentrated-cashew-apple-juice (CCAJ) was investigated. Total phenolics remained unchanged throughout fermentation period, whereas condensed tannins increased and hydrolysable tannins decreased indicating reduced astringency compounds. Antioxidant activity based on both DPPH and ABTS radical scavenging activities marginally declined in some stages but overall were sustained during fermentation. Although the DPPH· radical based antioxidant activity of fermented CAJ was greater than that of fermented 11.4 °Bx CCAJ, a higher ABTS·+ radical scavenging activity was found in fermented 11.4 °Bx CCAJ, reflecting higher water soluble antioxidants. Results also indicated that DPPH· radical scavenging activity was positively correlated to vitamin-C and condensed tannins but not hydrolysable tannins. ABTS·+ radical scavenging activity was also positively correlated to condensed tannins and not hydrolysable tannins. The vitamin-C that increased during initial 12 h fermentation, decreased from 2516 to 2150 mg AAE/L at the end of 72 h fermentation. Fermented CAJ had a remarkable sweet aroma with a fruity note of two major compounds; 3-methyl-1-butanol (14.20 × 107) and 2,6-dimethyl-4-heptanol (14.76 × 107). The high phytochemicals and volatile compounds in fermented CAJ indicated that it could serve as a functional beverage with potential health benefits with reduced astringency due to lower hydrolysable tannins.

Volatile flavour compounds, sensory characteristics and antioxidant activities of mungbean meal protein hydrolysed by bromelain.

Enzymatic mungbean meal protein hydrolysate (eb-MPH) is a novel natural flavour/antioxidant source. A 15% bromelain (w/w) concentration with a hydrolysis time of 12 h was the optimum conditions to produce eb-MPH, which showed the greatest antioxidant activities and sensory characteristics. eb-MPH was composed of oligopeptides that had low molecular weight (< 10 kDa) as well as surface hydrophobicity and high content of hydrophobic amino acids. eb-MPH contributed to DPPH (80) and ABTS (95%) scavenging activities and to savoury/sweet flavour volatile compounds (3-methyl-butanal, furfural and benzaldehyde), bouillon odour, sweet odour, chicken odour, meaty odour, moderate bitter taste and umami. In addition, principal component analysis (PCA) showed that 72.87% of the total variance confirmed the correlation between DH, S0, DPPH, ABTS, sensory characteristics and volatile flavour compounds. These results suggested that eb-MPH can be used as a natural food flavouring agent and antioxidant.

Enhancement of phenolics, resveratrol and antioxidant activity by nitrogen enrichment in cell suspension culture of Vitis vinifera.

Ammonium nitrate (NH4NO3), an important nitrogen source (34% N), has been used as an elicitor to stimulate plant growth and development as well as induce secondary metabolites under controlled conditions. In the present paper, we investigated the enhancement of cell biomass, total phenolics, resveratrol levels, and antioxidant activity of Vitis vinifera cv. Pok Dum by nitrogen enrichment (MS medium supplemented with NH4NO3 at 0, 500, 1,000, 5,000 and 10,000 mg/L). The highest accumulations of biomass, phenolics and resveratrol contents were observed at 8.8-fold (86.6 g DW/L), 15.9-fold (71.91 mg GAE/g DW) and 5.6-fold (277.89 µg/g DW) by the 14th day, in the medium supplemented with 500 mg/L NH4NO3. Moreover, the antioxidant activities of cultured grape cells estimated by the DPPH· and ABTS·+ assay were positively correlated with phenolics and resveratrol, and the maximum activity was also observed in cultured cells with 500 mg/L NH4NO3 at 176.11 and 267.79 mmol TE/100 g DW, respectively.

Bioactive peptides from brown rice protein hydrolyzed by bromelain: Relationship between biofunctional activities and flavor characteristics.

This study evaluated the biological properties of peptides from brown rice protein hydrolyzed by bromelain (eb-RPH) in relation to flavor characteristic. The fractionation into peptides < 1 kDa was observed to improve the DPPH, ABTS, and hydroxyl radical-scavenging activities (0.19, 2.28, and 24.64 mM Trolox, respectively), angiotensin-converting enzyme (ACE)-inhibitory activity (IC50 value of 0.20 ± 0.011 mg protein/mL), as well as bitter and umami tastes. The < 1 kDa fraction was further analyzed by liquid chromatography-electrospray ionization/mass spectrometry to identify amino acid sequence associated with biological activities and flavor characteristics. Eight peptides were identified. Most of the identified peptides contained features of previously reported ACE inhibitory and antioxidant peptides, especially peptide FGGSGGPGG and FGGGGAGAGG. Evaluation of flavor characteristics using BIOPEP database demonstrated that they had high occurrence frequencies of umami peptides (ESDVVSDL, GSGVGGAK, and SSVGGGSAG) and low Q-value (938.75 to 282.22), suggesting that these peptides may be used as a fortifying health ingredient with good taste. PRACTICAL APPLICATION: The fractionated brown rice protein hydrolysate (< 1 kDa) has the potential to serve as a functional food ingredient in nutraceutical food and beverage products that can provide health benefits with good taste. Information on amino acid composition and spatial conformation of peptide may aid us to better understand the molecular mechanisms involved in bioactivities and flavor of brown rice peptide for industrial applications.

Assessment of antioxidant properties of membrane ultrafiltration peptides from mungbean meal protein hydrolysates.

BACKGROUND: Bioactive peptides can prevent damage associated with oxidative stress in humans when consumed regularly. Recently, peptides have attracted immense interest because of their beneficial functional properties, safety and little or no side effects when used at high concentration. Most antioxidant peptides are small in size, less than 1 kDa, and contains a high proportion of hydrophobic amino acid. Particularly, tyrosine, leucine, alanine, isoleucine, valine, lysine, phenyalanine, cysteine, methionine and histidine in peptide chain exhibited high antioxidant activity. Mungbean meal protein (MMP) is highly abundant in hydrophobic amino acids. It indicated that MMP might be a good source of antioxidants. Therefore, the objectives were to optimize the conditions used to generate mungbean meal protein hydrolysate (MMPH) with antioxidant activity from bromelain and to investigate the antioxidant activities of different molecular weight (MW) peptide fraction. METHODS: Response Surface Methodology (RSM) was used for screening of the optimal conditions to produce MMPH. After that MMPH was fractionated using ultrafiltration membranes with different MW distributions. Crude-MMPH and four fractions were investigated for five antioxidant activities: 2,2,1-diphenyl-1-picrylhydrazyl (DPPH), hydroxyl, superoxide, ferric reducing antioxidant power (FRAP) and metal ion chelation activity. RESULTS: The optimal condition to produce the MMPH was 15% (w/w) of bromelain and hydrolysis time for 12 h which showed the greatest DPPH and ABTS radical scavenging activity. After mungbean protein from optimal condition was separated based on different molecular weight, the DPPH radical scavenging activity was the highest for the F4 (less than 1 kDa) peptide fraction. Metal ion chelating activity was generally weak, except for the F4 that had a value of 43.94% at a protein concentration of 5 mg/mL. The F4 also exhibited high hydroxyl and superoxide activities (54 and 65.1%), but moderate activity for ferric reducing antioxidant power (0.102 mmole Fe2+/g protein) compared to other peptide fractions and crude-MMPH. Molecular weight and amino acid were the main factors that determined the antioxidant activities of these peptide fractions. Results indicated that F4 had strong antioxidant potentials. DISCUSSION: The lowest MW fraction (less than 1 kDa) contributed to the highest DPPH, superoxide, hydroxyl and metal chelation activity because influence of low MW and high content of hydrophobic amino acid in peptide chain. Results from this study indicated that MMPH peptides donate protons to free radicals because they had significantly high DPPH value compared to superoxide, hydroxyl and FRAP, which reactions were electron donation. Moreover, MMPH peptides had the ability to inhibit transition metal ions because of highly abundant glutamic acid and aspartic acid in peptide chain.

Isolation and characterisation of antioxidative peptides from bromelain-hydrolysed brown rice protein by proteomic technique.

In this study, proteins from Thai brown rice (Khao Dawk Mali 105) were separated into albumin (2.18 %), globulin (3.98 %), glutelin (84.23 %), and prolamin (9.61 %) fractions, and were hydrolysed with various bromelain concentrations and hydrolysis times. Liquid chromatography-electrospray ionization/mass spectrometry (LC-ESI-MS/MS) was conducted to assess the composition, molecular weight (MW) distribution, and sequence of the resulting peptides, and showed that most peptides have a MW below 2000 Da (60-70 %). Glutelin fraction hydrolysates exhibited the highest 2,2'-azino-bis 3-ethylbenzthiazoline-6-sulfonic (ABTS•+) radical-scavenging (0.69 ± 0.04 µM trolox) and copper chelating (4.12 ± 0.01 mg ethylenediaminetetraacetic acid; EDTA) activities, which was further fractionated into six fractions using reversed-phase high-performance liquid chromatography. The fourth fraction showed the highest ABTS•+ scavenging (1.08 ± 0.03 mM trolox) and copper chelating (5.00 ± 0.02 mg EDTA) activity. LC-MS/MS analysis revealed that the peptides with MW less than 1500 Da and hydrophobic or aromatic N-terminal residues, such as SPFWNINAHS, MPVDVIANAYR, VVYFDQTQAQA, and VEVGGGARAP, possibly contributed to the highest antioxidant activity in fourth fraction.

Antibacterial effect of five Zingiberaceae essential oils.

Essential oil obtained by hydrodistillation and two different solvent extractions (petroleum ether and ethanol) from five Zingiberaceae species: ginger (Zingiber officinale Roscoe.), galanga (Alpinia galanga Sw.), turmeric (Curcuma longa L.), kaempferia (Boesenbergia pandurata Holtt.) and bastard cardamom (Amomum xanthioides Wall.) was characterized. Volatile components of all extracts were analyzed by gas chromatography-mass spectrometry (GC-MS). The major components of ginger, turmeric, galangal, bastard cardamom and kaempferia were zingiberene, turmerone, methyl chavicol, and gamma-terpinene, respectively. Their antibacterial effects towards Escherichia coli, Staphylococcus aureus, Bacillus cereus and Listeria monocytogenes were tested by a disc diffusion assay. Essential oil of kaempferia and bastard cardamom obtained by hydrodistillation extraction could inhibit growth of all tested bacteria. Essential oil of ginger extracted by hydrodistillation had the highest efficiency against three positive strains of bacteria (S. aureus, B. cereus and L. monocytogenes), with a minimum concentration to inhibit B. cereus and L. monocytogenes of 6.25 mg/mL.

Development of smart colourimetric starch-based indicator for liberated volatiles during durian ripeness.

The mechanical, physical and barrier properties of colourimetric starch-based films (CSBFs) were developed by adding natural polymers (chitosan, citric acid, carboxymethylcellulose, and kraft fibre). Novel volatile compound indicator films were prepared from starch (as a film matrix with 30% w/w sorbitol) using the casting method and adding natural polymers, and pH-dye (methyl red and bromothymol blue as indicators). CSBFs mixed with 0.1% chitosan improved the mechanical and barrier properties with a significant decrease in water vapour transmission rate, water solubility, and oxygen transmission rate, as well as improved tensile strength. Trials using liberated fruit aromas verified that CSBFs resulted in visible colour changes in the presence of mixed sulphur and ethyl alcohol aromas. Colour change in terms of the total colour difference of CSBFs was related to mixed sulphur and ethyl alcohol levels, thereby enabling CSBFs could be used to monitor real-time ripeness of durian volatiles.

A novel multi-biofunctional protein from brown rice hydrolysed by endo/endo-exoproteases.

Brown rice, which is a less allergenic food grain and contains essential amino acids, was hydrolysed by bromelain and PROTEASE FP51® to improve its functionalities and taste for food applications. The hydrolysate prepared by bromelain (eb-RPH) had high protein solubility, surface hydrophobicity, low molecular weight peptides, hydrophobic amino acids (leucine, valine and glycine) and flavor amino acids (glutamic acid and aspartic acid). The eb-RPH exhibited higher 1,1-diphenyl-2-picrylhydrazyl (DPPH˙) and 2,2'-azino-bis 3-ethylbenzthiazoline-6-sulfonic (ABTS˙(+)) radical-scavenging activities of 76.62% and 52.96%, respectively, and possessed a better foaming capacity (221.76%) and emulsifying capacity (32.34%) than the hydrolysate prepared by PROTEASE FP51® (ep-RPH) did. The eb-RPH gave the desired taste, which is attributed to volatile flavor compounds (benzaldehyde, benzeneacetaldehyde and 2-acetyl-1-pyrroline) and non-volatile flavor compounds, such as monosodium glutamate, 5'-guanosine monophosphate and 5'-inosine monophosphate (0.07, 0.03 and 0.05 mg mL(-1), respectively). Brown rice peptides generated by bromelain were novel bioactive peptides with multifunctional properties.

Assessment of biochemical and immunomodulatory activity of sulphated polysaccharides from Ulva intestinalis.

The biochemical characteristics and immunomodulatory activity of sulphated polysaccharides isolated from Ulva intestinalis and fractionated using a silica-silica column were investigated. The unfractionated (USP) and fractionated sulphated polysaccharides (FSP4, FSP30, and FSP32) consisted mostly of carbohydrates (4.84-26.55%) and sulphates (2.85-20.42%). Structural analyses showed that USP, FSP4, FSP30 and FSP32 had molecular weights of 300, 80, 110 and 140kDa, respectively. FSP30 exhibited the strongest DPPH radical scavenging activity. Moreover, FSP30 showed stronger immunomodulatory activities than UPS in term of stimulating the production of pro-inflammatory cytokines, including nitric oxide (NO), tumour necrosis factor-α (TNF-α), and interleukin-1ß (IL-1ß), in macrophage J774A.1 cells. USP and FSP30 were not cytotoxic to mouse macrophage at the tested concentrations (6.25-50µg/mL). The results suggested that U. intestinalis polysaccharides could be explored as potential antioxidant and immunomodulatory agents to be used as complementary medicine or functional foods.

Characteristics and antioxidant of Ulva intestinalis sulphated polysaccharides extracted with different solvents.

Ulva intestinalis, a tubular green seaweed, is a rich source of nutrient, especially sulphated polysaccharides. Sulphated polysaccharides from U. intestinalis were extracted with distilled water, 0.1N HCl, and 0.1N NaOH at 80°C for 1, 3, 6, 12, and 24h to study the effect of the extraction solvent and time on their chemical composition and antioxidant activity. Different types of solvents and extraction time had a significant influence on the chemical characteristics and antioxidant activity (p<0.05). Monosaccharide composition and FT-IR spectra analyses revealed that sulphated polysaccharides from all solvent extractions have a typical sugar backbone (glucose, rhamnose, and sulphate attached at C-2 or C-3 of rhamnose). Sulphated polysaccharides extracted with acid exhibited greater antioxidant activity than did those extracted with distilled water and alkali. The results indicated that solvent extraction could be an efficacious method for enhancing antioxidant activity by distinct molecular weight and chemical characteristic of sulphated polysaccharides.

Seafood-like flavour obtained from the enzymatic hydrolysis of the protein by-products of seaweed (Gracilaria sp.).

An enzymatic bromelain seaweed protein hydrolysate (eb-SWPH) was characterised as the precursor for thermally processed seafood flavour. Seaweed (Gracilaria fisheri) protein after agar extraction was hydrolysed using bromelain (enzyme activity=119,325 U/g) at 0-20% (w/w) for 0.5-24 h. Optimal hydrolysis conditions were determined using response surface methodology. The proposed model took into account the interaction effect of the enzyme concentration and hydrolysis time on the physicochemical properties and volatile components of eb-SWPH. The optimal hydrolysis conditions for the production of eb-SWPH were 10% bromelain for 3h, which resulted in a 38.15% yield and a 62.91% degree of hydrolysis value. Three free amino acids, arginine, lysine, and leucine, were abundant in the best hydrolysate. Ten volatile flavours of the best eb-SWPH were identified using gas chromatography/mass spectrometry. The predominant odourants were hexanal, hexanoic acid, nonanoic acid, and dihydroactinidiolide. The thermally processed seafood flavour produced from eb-SWPH exhibited a roasted seafood-like flavouring.

Characterization of cassava starch based foam blended with plant proteins, kraft fiber, and palm oil.

Cassava starch foam (CSF) trays blended with zein, gluten, soy protein, kraft fiber, and palm oil at various concentrations: 0, 5, 10 and 15% by weight of starch, were characterized. The addition of zein and gluten into CSF resulted in consolidated and homogeneous structural foams compared to its controls. Moreover, the flexural and compressive strength increased with increasing kraft, zein and gluten. CSF containing 15% kraft gave the highest flexural and compressive strength. However, the addition of palm oil into CSF gave the lowest flexural strength and compressive strength. The observed water absorption and water solubility index of CSFs blended with 15% zein and 15% gluten protein was lowest. Although kraft, zein and gluten could improve mechanical properties, water absorption and water solubility were greater than the expanded polystyrene foam (EPS). The CSF trays in this study might be an alternative for packing low water content foods.

Present and potential applications of cellulases in agriculture, biotechnology, and bioenergy.

Cellulase (CEL) presently constitutes a major group of industrial enzyme based on its diverse ranges of utilization. Apart from such current and well-established applications-as in cotton processing, paper recycling, detergent formulation, juice extraction, and animal feed additives-their uses in agricultural biotechnology and bioenergy have been exploited. Supplementation of CELs to accelerate decomposition of plant residues in soil results in improved soil fertility. So far, applying CELs/antagonistic cellulolytic fungi to crops has shown to promote plant growth performance, including enhanced seed germination and protective effects. Their actions are believed mainly to trigger plant defense mechanisms and/or to act as biocontrol agents that mediate disease suppression. However, the exact interaction between the enzymes/fungi and plants has not been clearly elucidated. Under mild conditions, removal of plant cell wall polysaccharides by CELs for protoplast preparation results in reduced protoplast damage and increased viability and yields. CELs have recently shown great potential in enzyme aid extraction of bioactive compounds from plant materials before selective extraction through enhancing release of target molecules, especially those associated with the wall matrix. To date, attempts have been made to formulate CEL preparation for cellulosic-based bioethanol production. The high cost of CELs has created a bottleneck, resulting in an uneconomic production process. The utilization of low-cost carbohydrates, strain improvement, and gene manipulations has been alternatively aimed at reducing the cost of CEL production. In this review, we focus on and discuss current knowledge of CELs and their applications in agriculture, biotechnology, and bioenergy.

Physicochemical and flavor characteristics of flavoring agent from mungbean protein hydrolyzed by bromelain.

Enzymatic bromelain mungbean meal protein hydrolysate (eb-MPH) was produced from mungbean meal protein isolate (MPI). Enzymatic bromelain, with a known protease activity of 98,652 (unit/g), was used at concentrations of 0, 2, 6, 10, 14 and 18% (w/w) and with hydrolysis times of 0.5, 3, 6, 12, and 24 h. The pH and temperature were controlled at 6.0 and 50 °C, respectively. It was found that the best treatment combination for eb-MPH production by response surface methodology (RSM) was 18% bromelain and a hydrolysis time of 3 h, resulting in the greatest degree of hydrolysis (% DH) and percent yield, with values of 61.04 and 45.63%, respectively. Results also showed that the phenylalanine, tyrosine and leucine contents of the optimally produced eb-MPH were 20.88, 14.50 and 10.93%, respectively. Twelve volatile compounds were identified using gas chromatography mass spectrometry in eb-MPH; benzaldehyde, 2-pentylfuran and furfural were the predominant odorants.