Janitha P.D. Wanasundara

Proteins of Brassicaceae Oilseeds and their Potential as a Plant Protein Source

Among the commercially cultivated Brassicaceae (Cruciferae) plants, Brassica juncea, Brassica napus, Brassica rapa, and Sinapis alba store significant amounts of oil and protein in the seed. At present, Brassica seed proteins are primarily used for livestock feeding based on the nutritional value. The point of curiosity is whether the present knowledge on the protein structure, biochemical characteristics, nutritive value, and the recovery processes are inadequate to develop Brassica proteins into a usable plant protein source or these proteins are of substandard for uses beyond animal nutrition applications. Cruciferin (11S) and napin (2S) are the predominant storage proteins of Brassicaceae seeds that contribute to different properties and functions. A gamut of information is available on the chemistry, nutritional value, as well as the functionality in foods, and associated non-protein components of canola/rapeseed storage proteins. The intention of this article is to critically review what is known about the predominant storage proteins of commercially produced Brassicaceae seeds relative to the above aspects and identify the knowledge gaps.

Physicochemical, thermal and functional characterisation of protein isolates from Kabuli and Desi chickpea (Cicer arietinum L.): a comparative study with soy (Glycine max) and pea (Pisum sativum L.)

BACKGROUNDnChickpea (Cicer arietinum L.) seeds are a good source of protein that has potential applications in new product formulation and fortification. The main objectives of this study were to analyse the physicochemical, thermal and functional properties of chickpea protein isolates (CPIs) and compare them with those of soy (SPI) and pea (PPI) protein isolates.nnnRESULTSnExtracted CPIs had mean protein contents of 728-853 g kg(-1) (dry weight basis). Analysis of their deconvoluted Fourier transform infrared spectra gave secondary structure estimates of 25.6-32.7% α-helices, 32.5-40.4% β-sheets, 13.8-18.9% turns and 16.3-19.2% disordered structures. CPIs from CDC Xena, among Kabuli varieties, and Myles, among Desi varieties, as well as SPI had the highest water-holding and oil absorption capacities. The emulsifying properties of Kabuli CPIs were superior to those of PPI and Desi CPIs and as good as those of SPI. The heat-induced gelation properties of CPIs showed a minimum protein concentration required to form a gel structure ranging from 100 to 140 g L(-1) . Denaturation temperatures and enthalpies of CPIs ranged from 89.0 to 92.0 °C and from 2.4 to 4.0 J g(-1) respectively.nnnCONCLUSIONnThe results suggest that most physicochemical, thermal and functional properties of CPIs compare favourably with those of SPI and are better than those of PPI. Hence CPI may be suitable as a high-quality substitute for SPI in food applications.

Dietary flaxseed intake exacerbates acute colonic mucosal injury and inflammation induced by dextran sodium sulfate

Flaxseed (FS), a dietary oilseed, contains a variety of anti-inflammatory bioactives, including fermentable fiber, phenolic compounds (lignans), and the n-3 polyunsaturated fatty acid (PUFA) α-linolenic acid. The objective of this study was to determine the effects of FS and its n-3 PUFA-rich kernel or lignan- and soluble fiber-rich hull on colitis severity in a mouse model of acute colonic inflammation. C57BL/6 male mice were fed a basal diet (negative control) or a basal diet supplemented with 10% FS, 6% kernel, or 4% hull for 3 wk prior to and during colitis induction via 5 days of 2% (wt/vol) dextran sodium sulfate (DSS) in their drinking water (n = 12/group). An increase in anti-inflammatory metabolites (hepatic n-3 PUFAs, serum mammalian lignans, and cecal short-chain fatty acids) was associated with consumption of all FS-based diets, but not with anti-inflammatory effects in DSS-exposed mice. Dietary FS exacerbated DSS-induced acute colitis, as indicated by a heightened disease activity index and an increase in colonic injury and inflammatory biomarkers [histological damage, apoptosis, myeloperoxidase, inflammatory cytokines (IL-6 and IL-1β), and NF-κB signaling-related genes (Nfkb1, Ccl5, Bcl2a1a, Egfr, Relb, Birc3, and Atf1)]. Additionally, the adverse effect of the FS diet was extended systemically, as serum cytokines (IL-6, IFNγ, and IL-1β) and hepatic cholesterol levels were increased. The adverse effects of FS were not associated with alterations in fecal microbial load or systemic bacterial translocation (endotoxemia). Collectively, this study demonstrates that although consumption of a 10% FS diet enhanced the levels of n-3 PUFAs, short-chain polyunsaturated fatty acids, and lignans in mice, it exacerbated DSS-induced colonic injury and inflammation.

The Effect of pH and NaCl Levels on the Physicochemical and Emulsifying Properties of a Cruciferin Protein Isolate

The influence of pH (3.0, 5.0, and 7.0) and ionic strength (0, 50, 100xa0mM NaCl) on the physicochemical and emulsifying properties of a cruciferin-rich protein isolate (CPI) was investigated. Surface charge on the CPI was found to substantially reduced in the presence of NaCl. Surface hydrophobicity was found to be the lowest for CPI at pHxa07.0 with 100xa0mM NaCl, and highest at pHxa03.0 without NaCl. Solubility was found to be lowest at pHxa05.0 and 7.0 without NaCl (<20xa0%), however greatly improved for all other pH and NaCl conditions (>80xa0%). Interfacial tension was found to be lowest at 10–11xa0mN/m for pHxa05.0–0xa0mM NaCl and pHxa07.0–50/100xa0mM NaCl, whereas under all other conditions interfacial tension was higher (15+ mN/m). Overall, NaCl has no effect on EAI at pHxa03.0 where it ranged between 18.8 and 19.4xa0m2/g. At pHxa05.0, EAI decreased from 21.1 to 12.8xa0m2/g as NaCl levels increased from 0 to 100xa0mM. At pHxa07.0, EAI values were found to decrease from 14.9 to 5.2xa0m2/g as NaCl levels were raised from 0 to 100xa0mM. Overall, ESI was reduced with the addition of NaCl from ~15.7xa0min at 0xa0mM NaCl to ~11.6xa0min and ~12.0xa0min for the 50 and 100xa0mM NaCl levels, respectively.