NOVEL ANTIOXIDANT AND RENIN-ANGIOTENSIN SYSTEM (RAS) INHIBITORY HYDROLYSATES FROM FLUTED-PUMPKIN AND CASHEW NUT PROTEINS Malomo, S.A.,1,2 Nwachukwu, I.D.,1 Girgih, A.T.,1,3 Idowu, A.O.,4 Aluko, R.E.,1 & Fagbemi, T.N.*2   1The Department of Human Nutritional Sciences, University of Manitoba, Winnipeg, Canada R3T 2N2 2The Department of Food Science and Technology, Federal University of Technology, Akure, Nigeria 3The Department of Food Science and Technology, Federal University of Agriculture, Makurdi, Nigeria 4The Department of Food Science and Technology, Mountain Top University, Prayer City, Lagos, Nigeria APRIL, 2017

INTRODUCTION OUTLINE Introduction Results obtained from the research work Conclusion

INTRODUCTION Several plant-sourced proteins have been explored and enzymatically processed (hydrolysis) to produce multifunctional bioactive protein-derived peptides Such bioactive peptides have been applied to human health in form of nutraceuticals or functional ingredients in some acclaimed natural health products. The elevated blood pressure, vascular oxidative stress and associated endothelial dysfunction are important contributing risk factors for developing cardiovascular diseases, such as hypertension. The renin–angiotensin system (RAS) is the primary physiological pathway that has been described for blood pressure regulation and management. (Udenigwe et al. 2017; Arise et al. 2017; Girgih et al. 2016; Malomo et al. 2015; Aluko et al. 2015)

Many plant protein-derived peptides are known to possess antihypertensive and antioxidative properties, which make them useful for enhancing metabolic health Therefore, development of functional and bioactive food-graded compounds that can mitigate these physiological conditions, can contribute to enhanced human health. This study, thus aimed to prepare novel antioxidant and RAS inhibitory peptides from fluted-pumpkin and cashew nut proteins (FPP and CNP). Both FPP and CNP were isolated and hydrolyzed using alcalase and pepsin to obtain hydrolysates (a-FPPH, p-FPPH, a-CNPH and p-CNPH, respectively). The resulting hydrolysates were sequentially passed through ultrafiltration membranes with molecular weight cut-off (MWCO) of different pore sizes to obtain<1, 1–3, 3–5, and 5–10 kDa peptide sizes.

RESULTS OBTAINED Fig 1- Degrees of hydrolysis (DH) of both cashew nut and fluted pumpkin proteins

hydrolysates and their membrane fractions Table 1- Amino acid compositions (%) of cashew nut and fluted-pumpkin hydrolysates and their membrane fractions

Fig 2- Hydroxyl-scavenging ability of both cashew nut and fluted-pumpkin protein hydrolysates and their membrane fractions

Fig 3- DPPH-scavenging ability of both cashew nut and fluted-pumpkin protein hydrolysates and their membrane fractions

Fig 4- Metal chelation ability of both cashew nut and fluted-pumpkin protein hydrolysates and their membrane fractions

Fig 5- Ferric reducing absorption power of both cashew nut and fluted-pumpkin protein hydrolysates and their membrane fractions

Fig 6- ACE inhibition capacity of both cashew nut and fluted-pumpkin protein hydrolysates

Fig 7- ACE inhibition capacity of cashew nut protein hydrolysate and its membrane fractions at different hours of hydrolysis

Fig 8- ACE inhibition capacity of fluted-pumpkin protein hydrolysate and its membrane fractions different hours of hydrolysis

Fig 9- Renin inhibition capacity of both cashew nut and fluted-pumpkin protein hydrolysates

Fig 10- Renin inhibition capacity of both cashew nut and fluted-pumpkin protein hydrolysates and their membrane fractions

SUMMARY OF THE STUDY FINDINGS The best OH--scavenging, DPPH--scavenging and ferric reducing capacities were obtained at <1 kDa molecular weight fractions (MWF) for both CNP and FPP Meanwhile, the best metal chelation capacity was obtained at all the molecular weight fractions (MWF), i.e. <1 to 10 kDa for both CNP and FPP The ACE inhibition was best attained at enzyme concentrations of 2% pepsin and 3% alcalase for CNP and FPP, respectively. Contrarily, the renin inhibition was best attained at enzyme concentrations of 2% alcalase and 3% pepsin for CNP and FPP, respectively.

CONCLUSION The protease-hydrolysis of fluted pumpkin and cashew nut protein isolates yielded peptides with in vitro antioxidant and RAS inhibitory activities thus, creating a new evolution in the peptidometric studies Both fluted pumpkin and cashew nut proteins contain low molecular weight peptides with potentiality of fast absorption in the gastrointestinal tract (GIT) Value-added utilization of these traditional crops could increase economic value of the crop with substantial benefits to farmers, processors and Nigeria.

ACKNOWLEDGEMENTS Members of Dr. Aluko lab’s group for their assistance Dennis Labossiere for his technical assistance NSERC Discovery Grant

PLATES FOR CASHEW AND FLUTED PUMPKIN FRUITS AND SEEDS

REFERENCES Udenigwe, C.C., Girgih, A.T., Mohan, A., Gong, M., Malomo, S.A., & Aluko, R.E. 2017. Antihypertensive and bovine plasma oxidation-inhibitory activities of spent hen meat protein hydrolysates. J. Food Biochem., (In Press). Arise, A.K., Alashi, A.M., Nwachukwu, I.D., Malomo, S.A., Aluko, R.E., & Amonsou, E. 2017. Inhibitory properties of bambara protein hydrolysate and its membrane fractions against angiotensin converting enzymes, renin and free radicals. J. Sci. Food Agric., (In Press). Girgih, A.T., Onuh, J.O., Nwachukwu, I.D., Malomo, S.A., & Aluko, R.E. 2016. Antihypertensive properties of pea protein hydrolysate during short and long term oral administration to spontaneously hypertensive rats. J. Food Sci., 81(5), H1281–1287. Malomo, S.A., & Aluko, R.E. 2015. Conversion of a hemp seed industrial waste product into a functional protein isolate through membrane ultrafiltration coupled with enzymatic digestion of fibre and phytate. Inno. Food Sci. Emerging Tech., 31, 151-159.  Aluko, R.E., Girgih, A.T., He, R., Malomo, S.A., Li, H., Offengenden, M., & Wu, J. 2015. Structural and functional characterization of yellow field pea seed (Pisum sativum L.) protein-derived antihypertensive peptides. Food Res. Int., 77, 10-16.

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