Enhancement of Bioactive Compounds and Antioxidant Activities of Olive (<Emphasis Type="Italic">Olea europaea</Emphasis> L.) Leaf Extract by Instant Controlled Pressure Drop

In this work, the effect of Détente Instantanée Contrôlée (DIC) (French for instant controlled pressure drop) on the total polyphenol, flavonoids, α-tocopherol contents, and antioxidant activities of olive leaves was studied. Olive leaf extracts were pre-treated at one cycle DIC under 0.1 MPa pressure for 11 s and followed by an extraction with 95% ethanol at 55 °C during 3 h. The phenolic compounds, flavonoïds, oleuropein, and α-tocopherol contents were determined, showing 66.63 mg gallic acid equivalent (GAE)/g db, 12 mg catechin equivalent (CE)/g db, 43.9 mg/g db, and 0.15 mg/g db for the untreated leaves against 239.37 mg GAE/g db, 28 mg CE/g db, 70.3 mg/g db, and 0.59 mg/g db for DIC-treated leaves, respectively. Therefore, DIC allows more availability of bioactive compounds contributing to a high antiradical activity (DPPH) compared to a synthetic antioxidant butylated hydroxytoluene (BHT). Both extracts showed a total antioxidant capacity (method of phosphomolybdenum) greater than that of the standard BHT. Likewise, both extracts have a reducing power (FRAP test) significant concentration-dependent. The DIC-treated leaves showed a higher antioxidant capacity compared to that of untreated leaves. Thus, DIC could be an effective treatment to promote the extraction of bioactive molecules of high antioxidant activities from olive leaves.     

Determination of Mineral Composition and Heavy Metal Content of Some Nutraceutically Valued Plant Products

Minerals and heavy metal concentrations of 23 plants (arial parts, leaves, bark, stem, root, rhizome, dried berries, seeds) possessing health-promoting effects and used in indigenous medicines (as medicinal food) were determined using inductively coupled plasma atomic spectrometry. Vital essential minerals and heavy metals were present in all the samples analyzed. The majority of the plant materials were rich in some of the essential minerals like Na, K, Ca, Fe, Mg, Cu, Mn, and Zn, which are known to be beneficial for health. The plant material of Vitiveria zizinalis had highest concentration of toxic heavy metals, including arsenic (53.1 mg/100 g), chromium (6.74 mg/100 g), cobalt (10.2 mg/100 g), mercury (3.6 mg/100 g), and nickel (3.28 mg/100 g). Results of the present study provide vital data on the availability of some essential minerals, which can be useful to provide dietary information for designing value-added foods and for food biofortification. Apart from this, data on the contaminant levels of heavy metals highlights the necessity on the quality and safety concerns about their use.     

Nanometer-scale chemical heterogeneities of black carbon materials and their impacts on PCB sorption properties: soft X-ray spectromicroscopy study

Synchrotron-based soft X-ray spectromicroscopy was used to probe nanometer-scale chemical heterogeneities of black carbon (BC) materials, including anthracite coal, coke, and activated carbon (AC), and to study their impact on the partitioning of one type of polychlorinated biphenyls (PCB-166: 2,3,4,4',5,6 hexachloro biphenyl) onto AC particles. Various carbon species (e.g., aromatic, ketonic/ phenolic, and carboxylic functional groups) were found in all of the BC materials examined, and impurities (e.g., carbonate and potassium ions in anthracite coal) were identified in nanometer-scale regions of these samples. We show that these chemical heterogeneities in AC particles influence their sorption of hydrophobic organic compounds (HOCs). PCB-166 was found to accumulate preferentially on AC particles with the highest content of aromatic functionalities. These new findings from X-ray spectromicroscopy have the following implications for the role of BC materials in the environment: (1) the functional groups of BC materials vary on a 25-nanometer scale, and so does the abundance of the HOCs; (2) molecular-level characterization of HOC sorption preferences on AC will lead to an improved understanding of AC sorption properties for the remediation of HOCs in soils and sediments.     

Isolation and characterisation of collagen from the ribbon jellyfish (Chrysaora sp.)

Pepsin‐solubilised collagen from the ribbon jellyfish (Chrysaora sp., morphotype 1) umbrella (JPSC) was isolated and characterised. The yield of collagen varied (9–19%, based on ash‐free dry weight) depending on the amount of pepsin used. Type II collagen was the major component of extracted collagen. The peptide map of JPSC differed from that of standard collagen type II, which indicates their different primary structures. FTIR spectra of JPSC, however, did not differ significantly from those of type II collagen. The T_max of JPSC was 37.38 °C, which is higher than that of other marine collagens. Glycine was the main amino acid in JPSC (320 residues per 1000 residues), followed by glutamic acid, alanine, proline, aspartic acid and hydroxyproline. The isoelectric point of JPSC was 6.64. These results indicate that this jellyfish species has the potential to be a marine source of type II collagen that can be used in place of land‐based sources.     

Physicochemical Properties of Carboxy-methylated Sago (Metroxylon sagu) Starch

ABSTRACT: Carboxymethyl starch (CMS) with degree of substitution (DS) ranging from 0.1 to 0.32 was prepared from sago ( Metroxylon sagu ) starch in non-aqueous medium using isopropanol as a solvent. The physico-chemical, rheological, and thermal properties of the starches were investigated. At room temperature (25 °C), CMS hydrated readily, resulting in higher swelling power compared with native (unmodified) starch. Light microscopy revealed that CMS granules imbibed more water than native starch at room temperature and thus caused a larger increase in granule size. Some of the CMS granules lost their integrity. Scanning electron microscopic observation revealed fine fissures on the surface of CMS (DS 0.32) granules compared with a relatively smooth surface of native starch granules. Carboxymethylated sago starch exhibited excellent dispersibility and cold water solubility as judged by the absence of peak viscosity in the pasting profile (determined by Rapid ViscoAnalyzer). Pasting profile of CMS was qualitatively similar to pregelatinized starch. Despite exhibiting greater swelling power, CMS showed significantly lower pasting viscosity compared with the native starch. Intrinsic viscosity was also greatly reduced by carboxymethylation. Studies using differential scanning calorimetry (DSC) showed that transition temperatures and enthalpies decreased with an increase of degree of substitution. CMS at higher substitution levels (DS 0.27 and 0.32) showed significantly lower retrogradation tendency, as indicated by lower setback, absence of DSC endotherm upon storage at 4 °C and lower syneresis upon repeated freeze-thaw cycles. The results suggested that retrogradation might be effectively retarded by the presence of the bulky carboxymethyl group.     

Thermal Behavior of Selected Starches in Presence of Other Food Ingredients Studied by Differential Scanning Calorimetery (DSC)–Review

ABSTRACT: This review article highlights the thermal behaviors of selected starches that were studied using differential scanning calorimetery (DSC) with data shown in various research publications. The starches of sago, potato, sweet potato, cassava, yam, and corn are included in this overview. Our examinations indicate that thermal properties are highly affected by the type of starch, its amylose/amylopectin content, and the presence of other food ingredients such as sugar, sodium chloride, water, milk, hydrocolloids, and meat. When the heating temperatures of the starches were increased, the DSC measurements also showed an increase in the temperatures of the gelatinization (onset [T_o], peak [T_p], and conclusion [T_c]). This may be attributed to the differences in the degree of crystallinity of the starch, which provides structural stability and makes the granule more resistant to gelatinization.     

Nonmeat Protein Alternatives as Meat Extenders and Meat Analogs

Abstract: The direct consumption of vegetable proteins in food products has been increasing over the years because of animal diseases, global shortage of animal protein, strong demand for wholesome and religious (halal) food, and economic reasons. The increasing importance of legume and oilseed proteins in the manufacturing of various functional food products is due to their high‐protein contents. However, the greatest obstacle to utilizing these legumes and oilseeds is the presence of antinutrients; but these antinutrients can be successfully removed or inactivated by employing certain processing methods. In contrast, the potential negative impact of the antinutrients is partially balanced by the fact that they may have a health‐promoting role. Legumes and oilseeds provide well‐balanced amino acid profiles when consumed with cereals. Soybean proteins, wheat gluten, cottonseed proteins, and other plant proteins have been used for texturization. Texturized vegetable proteins can extend meat products while providing an economical, functional, and high‐protein food ingredient or can be consumed directly as a meat analog. Meat analogs are successful because of their healthy image (cholesterol free), meat‐like texture, and low cost. Mycoprotein is fungal in origin and is used as a high‐protein, low‐fat, health‐promoting food ingredient. Mycoprotein has a good taste and texture. Texturized vegetable proteins and a number of mycoprotein products are accepted as halal foods. This article summarizes information regarding the molecular, nutritional, and functional properties of alternative protein sources to meat and presents current knowledge to encourage further research to optimize the beneficial effects of alternative protein sources.