Pectin and modified pectin differ in the structure of the chains in which the modified version of pectin is shorter in length, non-branched, and galactose-rich. These differences in structure may be exploited for the removal of heavy metals. Durian (Durio zibethinus) rind, that is regarded as agri-food waste was processed into durian rind pectin (DRP) and modified durian rind pectin (mDRP). DRP and mDRP were evaluated as biosorbent for removal of toxic heavy metals (Pb(II), Cd(II), Cu(II), Zn(II) and Ni(II)) and were compared with two commercial products; citrus pectin (CP) and modified citrus pectin (MCP). In general, the order of removal of heavy metals by all biosorbents was Cu(II) > Pb(II) > Ni(II) > Zn > Cd(II). Except for the removal of Pb(II), the order of effectiveness of heavy metal removal of the biosorbents was MCP > mDRP > CP > DRP. MCP, a commercial biosorbent showed the best biosorbent ability, and mDRP a waste product from durian was also a favorable sorber that should be considered for sorption and removal of heavy metals.
The physical attributes (pH and colour), cooking yield, textural and mechanical properties (firmness, tensile and texture profiles analyses) and structural breakdown properties (multiple extrusion cell with added artificial saliva) of five yellow alkaline noodle (YAN) formulations were studied. Samples used were noodles with (a) typical formulation (control), (b) soy protein isolate (SPI), (c) soy protein isolate plus microbial transglutaminase enzyme (SPI/MTGase), (d) green banana pulp flour (GBPu) and (e) green banana peel flour (GBPe). Compared to other noodles SPI/MTGase noodle showed significantly (P < 0.05) higher values in terms of textural, mechanical and breakdown properties. Incorporating SPI, banana pulp and peel flours into the noodles had imposed some differences on most of the mechanical and textural parameters from the control YAN. However, these noodles could not be clearly distinguished in term of structural breakdown properties.
Four types of soft dates (SD), three types of semi-dried dates (SDD) and one type of dried dates (DD) were used in this study. The antioxidant activities were assessed using TEAC method (ABTS assay) and the ferric reducing/antioxidant power method (FRAP assay), while total phenolic content (TPC) and total flavonoid content (TFC) were measured using Folin-Ciocalteau and aluminum chloride colorimetric methods. Multivariate analysis of variance (MANOVA), discriminant analysis (DA) and principal component analysis (PCA) were used to analyze the data. MANOVA showed a strong significant difference between the eight types of dates. DA identified the relative contribution of each parameter in distinguishing the dates. DA also identified two functions responsible for discriminating the dates and showed the difference between different types of dates. The first function distinguished DD from other types of dates, whilst the second function discriminated SD and SDD, affording 100% correct assignation. PCA identified only one component responsible for explaining 98.85% of the total variance in antioxidant data. It is suggested that the TEAC method and the quantitative determination of TPC and TFC was suitable for differentiation of dates and quality control.