Physicochemical characterization of alkali treated fractions from corncob and wheat straw and the production of nanofibres

Raw cereal materials (CM) (corncob and wheat straw) were alkaline treated to produce insoluble fibrous residues (IF) and soluble fibrous residues (SF). Physicochemical properties of each portion were evaluated. CM contained high amounts of dietary fibre (DF; 49.87–68.65%), while IF and SF mainly contained insoluble and soluble DF, respectively. CM and IF contained essential minerals (calcium, copper, iron, potassium, magnesium and phosphorus) while SF was free from heavy metals. CM and IF also exhibited DPPH radical scavenging ability (54.25 to 77.24%), good emulsification ability (3.73–5.29%) and emulsion stability (75.00–86.94%), mineral binding capacity (calcium, copper, iron, zinc), water holding capacity (2.82–6.01 g_water/g_sample) and oil holding capacity (2.61–4.00 g_oil/g_sample). IF and SF could be potentially developed into new functional food materials. The successful production of SF into nanofibres by electrospinning showed potential applications as delivery systems for bioactive and functional ingredients.     

Nanotech: propensity in foods and bioactives

Nanotechnology is seeing higher propensity in various industries, including food and bioactives. New nanomaterials are constantly being developed from both natural biodegradable polymers of plant and animal origins such as polysaccharides and derivatives, peptides and proteins, lipids and fats, and biocompatible synthetic biopolyester polymers such as polylactic acid (PLA), polyhydroxyalkonoates (PHA), and polycaprolactone (PCL). Applications in food industries include molecular synthesis of new functional food compounds, innovative food packaging, food safety, and security monitoring. The relevance of bioactives includes targeted delivery systems with improved bioavailability using nanostructure vehicles such as association colloids, lipid based nanoencapsulator, nanoemulsions, biopolymeric nanoparticles, nanolaminates, and nanofibers. The extensive use of nanotechnology has led to the need for parallel safety assessment and regulations to protect public health and adverse effects to the environment. This review covers the use of biopolymers in the production of nanomaterials and the propensity of nanotechnology in food and bioactives. The exposure routes of nanoparticles, safety challenges, and measures undertaken to ensure optimal benefits that outweigh detriments are also discussed.     

Enhanced Growth of Lactobacilli in Soymilk upon Immobilization on Agrowastes

ABSTRACT: Cell immobilization is an alternative to microencapsulation for the maintenance of cells in a liquid medium. The objective of this study was to evaluate the effects of agrowastes from durian (Durio zibethinus), cempedak (Artocarpus champeden), and mangosteen (Garcinia mangostana) as immobilizers for lactobacilli grown in soymilk. Rinds from the agrowastes were separated from the skin, dried, and ground (150 μm) to form powders and used as immobilizers. Scanning electron microscopy revealed that lactobacilli cells were attached and bound to the surface of the immobilizers. Immobilized cells of Lactobacillus acidophilus FTDC 1331, L. acidophilus FTDC 2631, L. acidophilus FTDC 2333, L. acidophilus FTDC 1733, and L. bulgaricus FTCC 0411 were inoculated into soymilk, stored at room temperature (25 °C) and growth properties were evaluated over 168 h. Soymilk inoculated with nonimmobilized cells was used as the control. Utilization of substrates, concentrations of lactic and acetic acids, and changes in pH were evaluated in soymilk over 186 h. Immobilized lactobacilli showed significantly better growth (P < 0.05) compared to the control, accompanied by higher production of lactic and acetic acids in soymilk. Soymilk containing immobilized cells showed greater reduction of soy sugars such as stachyose, raffinose, sucrose, fructose, and glucose compared to the control (P < 0.05).     

A hash trie filter method for approximate string matching in genomic databases

In genomic databases, approximate string matching with k errors is often applied when searching genomic sequences, where k errors can be caused by substitution, insertion, or deletion operations. In this paper, we propose a new method, the hash trie filter, to efficiently support approximate string matching in genomic databases. First, we build a hash trie for indexing the genomic sequence stored in a database in advance. Then, we utilize an efficient technique to find the ordered subpatterns in the sequence, which could reduce the number of candidates by pruning some unreasonable matching positions. Moreover, our method will dynamically decide the number of ordered matching grams, resulting in the increase of precision. The simulation results show that the hash trie filter outperforms the well-known (k+s) q-samples filter in terms of the response time, the number of verified candidates, and the precision, under different lengths of the query patterns and different error levels.     

Development of a probiotic delivery system from agrowastes, soy protein isolate, and microbial transglutaminase

Abstract: Probiotic delivery system was developed via the use of microbial transglutaminase (MTG) cross‐linked soy protein isolate (SPI) incorporated with agrowastes such as banana peel (BE), banana pulp (BU), and pomelo rind (PR). Inoculums of Lactobacillus bulgaricus FTDC 1511 were added to the cross‐linked protein matrix. The incorporation of agrowastes had significantly (P < 0.05) reduced the strength, pH value, and the lightness of the SPI gel carriers, while sodium dodecyl sulfate‐polyacrylamide gel electrophoresis profiles revealed that the occurring cross‐links within the SPI gel carriers were attributed to the addition of MTG. Scanning electron microscope micrographs illustrated that SPI carriers containing agrowastes have exhibited a less‐dense protein matrix. All the SPI carriers possessed maximum swelling ratio at 4 to 4.5 within 15 min in simulated gastric fluid (SGF), whereas the maximum swelling ratios of SPI/BE, SPI/BU, and SPI/PR were higher compared to that of control in simulated intestinal fluid (SIF). Additionally, SPI carriers in SGF medium did not show degradation of structure, whereas a major collapse of network was observed in SIF medium, indicating controlled‐release in the intestines. The addition of agrowastes into SPI carriers led to a significantly (P < 0.0001) lower release of L. bulgaricus FTDC 1511 in SGF medium and a higher release in SIF medium, compared to that of the control. SPI carriers containing agrowastes may be useful transports for living probiotic cells through the stomach prior to delivery in the lower intestines. Practical Application: Agrowastes could be utilized as a new probiotic carrier for enhanced gastrointestinal transit and during storage. This also reduces the amount of agrowastes accumulated.     

Development of probiotic carriers using microbial transglutaminase-crosslinked soy protein isolate incorporated with agrowastes

BACKGROUND: Probiotics are live micro‐organisms that exert beneficial effects on their host. A high survival rate during gastrointestinal transit and storage is often desirable. The main aim of this study was to develop protective carriers for probiotics via the use of enzymatically crosslinked soy protein isolate incorporated with agrowastes such as banana peel, banana pulp, cempedak rind and cocoa rind. RESULTS: Addition of agrowastes significantly (P < 0.05) reduced the strength and pH and darkened the colour of the gel. Sodium dodecyl sulfate polyacrylamide gel electrophoresis indicated that microbial transglutaminase induced crosslinking in the carrier network, while scanning electron microscopy showed that agrowaste addition resulted in a denser, finer and thinner protein network. Controlled release and swelling tests of the carriers in simulated gastric and intestinal fluids showed a low release under gastric conditions but a high release under intestinal conditions. The viability of Lactobacillus acidophilus FTDC 1331 incorporated in carriers containing agrowastes was more stable during storage at 4 °C for 28 days compared with the control (P < 0.05). CONCLUSION: The results of this study showed that agrowastes could be utilised as new probiotic carriers for enhanced gastrointestinal transit and storage. Copyright © 2011 Society of Chemical Industry     

The Improvement of Hypertension by Probiotics: Effects on Cholesterol, Diabetes, Renin, and Phytoestrogens

Probiotics are live organisms that are primarily used to improve gastrointestinal disorders such as diarrhea, irritable bowel syndrome, constipation, lactose intolerance, and to inhibit the excessive proliferation of pathogenic intestinal bacteria. However, recent studies have suggested that probiotics could have beneficial effects beyond gastrointestinal health, as they were found to improve certain metabolic disorders such as hypertension. Hypertension is caused by various factors and the predominant causes include an increase in cholesterol levels, incidence of diabetes, inconsistent modulation of renin and imbalanced sexual hormones. This review discusses the antihypertensive roles of probiotics via the improvement and/or treatment of lipid profiles, modulation of insulin resistance and sensitivity, the modulation of renin levels and also the conversion of bioactive phytoestrogens as an alternative replacement of sexual hormones such as estrogen and progesterone.     

Mechanisms of cholesterol removal by lactobacilli under conditions that mimic the human gastrointestinal tract

Five strains of lactobacilli were studied for their ability to remove cholesterol in vitro under conditions that mimic the human gastrointestinal tract. The highest assimilation of cholesterol was observed in media supplemented with oxgall and the lowest in the presence of taurocholic acid. Scanning electron micrographs showed that cholesterol was adhered to the cellular surface of lactobacilli cells. Resting and dead cells were able to remove cholesterol although in small amounts. Additionally, inhibition of cholesterol micelles formation was observed in the presence of bile salts. All strains were able to deconjugate bile salts, where higher deconjugation was observed in the presence of sodium glycocholate compared with other bile salts studied. All strains also exhibited bile salt hydrolase activity and most strains showed higher substrate specificity towards glycine-conjugated bile than towards taurine-conjugated bile. The results indicated that lactobacilli could remove cholesterol in vitro via various mechanisms, and may exert such hypocholesterolaemic effects in vivo.     

Evaluation of Free Radical Scavenging Activity and Antioxidant Potential of a Few Popular Green Leafy Vegetables of Malaysia

In this study, phenolic contents and antioxidant activity of five popular green leafy vegetables of Malaysia—Kangkung, Kucai, Di Huang Miao, Ubi Keledek, and Yaw Mak Choy—were evaluated. Methanol, acetone, and distilled water were the solvent systems used for extraction. The antioxidant capacity of the extracts was evaluated using ferric reducing antioxidant potential assay and the free radical scavenging capacity was evaluated using the DPPH· radical-scavenging assay. The total flavonoids, flavonols, and tannins were also quantified. The efficacy of the three solvents used for extraction differed significantly for both the levels of antioxidants and free radical scavenging activity. In general, methanol was the best of the three solvents for extraction of antioxidants. The results of this study will be useful for health conscious consumers, and they will provide a basis for future exploration of these green leafy vegetables as potential sources of natural antioxidants for food and nutraceutical applications.