Chemical composition, molecular weight distribution, secondary structure and effect of NaCl on functional properties of walnut (Juglans regia L) protein isolates and concentrates

Abstract

Chemical composition, molecular weight distribution, secondary structure and effect of sodium chloride concentration on functional properties of walnut protein isolates, concentrates and defatted walnut flour were study. Compared with walnut protein concentrates (75.6%) and defatted walnut flour (52.5%), walnut protein isolates contain a relatively high amount of protein (90.5%). The yield of walnut protein isolates and concentrates was 43.2% and 76.6%, respectively. In molecular weight distribution study, Walnut protein isolates showed one peak with molecular weight of 106.33 KDa (100%) and walnut protein concentrates showed four peaks with molecular weight of 16,725 KDa (0.8%),104.943 KDa(63.9%), 7.3 KDa (11.4%), 2.6 KDa (23.9%). The secondary structure of walnut protein isolates was similar to that of walnut protein concentrates, but was differ from that of defatted walnut flour. The addition of sodium chloride (0~1 M) could improve the functionality of walnut protein concentrates, isolates and defatted walnut flour. The maximum solubility, water absorption capacity, emulsifying properties and foaming properties of walnut protein isolates, concentrates and defatted walnut flour were at sodium chloride solutions of 1.0 M, 0.6 M, 0.4 M, 0.6 M, respectively. The solubility of walnut protein concentrates (32.5%) in distilled water with 0 M sodium chloride was lower than that of walnut protein isolates (35.2%). The maximum solubility of walnut protein isolates, concentrates and defatted walnut flour in solution were 36.8%, 33.7% and 9.6% at 1.0 M sodium chloride solutions, respectively. As compared with other vegetable proteins, walnut protein isolates and concentrates exhibited better emulsifying properties and foam stability.

Effect of maleylation on physicochemical and functional properties of rapeseed protein isolate

“…The solution was centrifuged for 15 min at 8586 × g (4°C), and the supernatant were filtered through a 0.22 μm cellulose membrane filter and analyzed by a Waters GPC system (515 HPLC Pump), equipped with a Waters HSPgel™ AQ 3.0 column (6.0 × 150 mm) and a Waters 2489 UV detector (Mao and Hua 2014). Following chromatographic conditions were applied: injection volume = 20 μl; isocratic flow rate = 0.3 ml/min; elution solvent = Milli-Q water containing 0.3 M NaCl; and run time = 15 min.…”

Separation and purification of angiotensin-I-converting enzyme (ACE) inhibitory peptides from walnuts (Juglans regia L.) meal

“…Studies of walnut protein or peptides were reported previously, e.g., the chemical composition, molecular weight distribution of walnut protein isolates and concentrates [17], the effect of different oil extraction methods on protein characteristics of walnut [18], and the antioxidant activities of the walnut hydrolysates [19]. Statistics show that China's walnut production is ranked first globally, but it is still far from self-sufficient in terms of processing capabilities and utilization.…”

Fatty Acids Content of Kahai (Caryodendron Orinocense Karst) Seeds Cultivated in Amazonian of Ecuador

“…Olive oil contains few omega 6 and omega 3 fatty acids with 9.0% and 1.0%, respectively, and macadamia oil contains 3.22 % of omega 6 and 1.79% of omega 3 ( Table 2). Kahai oil has a similar profile of fatty acids when it is compared to walnut Juglans regia with a high content of omega 6 and a good content of omega 9, both oils presenting a few content of omega 3 [10,11]. Walnut has been considered as a healthy food due to its capacity to reduce cardiovascular diseases risk.…”