255
DPP-IV secretion (Cicero et al. 2016; Horner et al. 2016). Milk-derived caseins and
whey proteins are reported to have a stimulating effect on secretion of insulin in
obese, healthy, pre-diabetic and type-2 diabetes subjects (Power et al. 2009; Pal and
Ellis 2010; Pal et al. 2010; Jonker et al. 2011; Hoefle et al. 2015). Bovine milk
caseins like β-casein are very good sources of DPP-IV inhibitors (Patil et al. 2015).
The insulinotropic effect of whey proteins was more pronounced compared to
caseins. Also, protein hydrolysates of whey showed faster effect than intact proteins
consumption (Horner et al. 2016). Intact whey protein has also shown enhanced
GIP (Hall et al. 2003; Frid et al. 2005; Nilsson et al. 2007) and GLP-1 (Ma et al.
2009; Akhavan et al. 2014) response. Whey protein supplementation has demonstrated insulin release and postprandial glucose control in clinical trials of healthy
and type 2 diabetic subjects (Sousa et al. 2012). It is hypothesized that whey proteins release peptides while passing through gastrointestinal tract and help regulate
the glycaemic response (Akhavan et al. 2010). A study on obese mice also showed
an improvement in insulin secretion is response to glucose and lower blood glucose
levels when orally administered with whey protein hydrolysates (Gaudel et al.
2013). Moreover, recent studies have shown DPP-IV inhibitory effects of bovine
casein and whey protein derived peptides (Gunnarsson et al. 2006; Tulipano et al.
2011; Nongonierma and Fitzgerald 2013). Peptides derived from β-lactoglobulin
are efficient DPP-IV inhibitors: peptide with sequence VAGTWY was able to demonstrate hypoglycaemic effects in mice in the oral glucose tolerance test (Uchida
et al. 2011). An in-silico study also showed both casein and whey proteins as precursors of DPP-IV inhibitory peptides (Lacroix and Li-Chan 2012).
Other important enzymes that play a role in insulin modulation are α-glucosidase
and α- amylase. Hence, the inhibition of these enzymes may lead to delayed carbohydrate digestion and glucose absorption may be helpful in managing diabetes
(Bharatham et al. 2008; Vankudre et al. 2015). Milk fermentation with L. bulgaricus
and L. acidophilus showed increased α-glucosidase inhibition (Apostolidis et al.
2007). In a different study, peptic digestion of whey proteins displayed high
α-glucosidase inhibition (Lacroix and Li-Chan 2013). Thus, milk derived bioactive
peptides may help in glycemic management strategy, although further work is
needed to fully determine the bioavailability of the peptides in humans.
Antihypertensive Effects
One of the major risk factors for cardiovascular disease is elevated blood pressure
(Erdmann et al. 2008). The angiotensin-I converting enzyme (ACE) helps regulate
blood pressure by catalyzing the conversion of angiotensin I to angiotensin II (a
potent vasoconstrictor) and breakdown of bradykinin (a vasodilator) (Sánchez and
Vázquez 2017). Since angiotensin II elevates the blood pressure levels, inhibiting
ACE is a way to control blood pressure (Korhonen and Pihlanto 2007). Inhibitors of
ACE are currently available in the markets to treat hypertnesio like capotril, alacepril, lisinopril and enalapril. However, their synthetic nature causes unwanted side
Nutraceutical Properties of Bioactive Peptides
DPP-IV secretion (Cicero et al. 2016; Horner et al. 2016). Milk-derived caseins and
whey proteins are reported to have a stimulating effect on secretion of insulin in
obese, healthy, pre-diabetic and type-2 diabetes subjects (Power et al. 2009; Pal and
Ellis 2010; Pal et al. 2010; Jonker et al. 2011; Hoefle et al. 2015). Bovine milk
caseins like β-casein are very good sources of DPP-IV inhibitors (Patil et al. 2015).
The insulinotropic effect of whey proteins was more pronounced compared to
caseins. Also, protein hydrolysates of whey showed faster effect than intact proteins
consumption (Horner et al. 2016). Intact whey protein has also shown enhanced
GIP (Hall et al. 2003; Frid et al. 2005; Nilsson et al. 2007) and GLP-1 (Ma et al.
2009; Akhavan et al. 2014) response. Whey protein supplementation has demonstrated insulin release and postprandial glucose control in clinical trials of healthy
and type 2 diabetic subjects (Sousa et al. 2012). It is hypothesized that whey proteins release peptides while passing through gastrointestinal tract and help regulate
the glycaemic response (Akhavan et al. 2010). A study on obese mice also showed
an improvement in insulin secretion is response to glucose and lower blood glucose
levels when orally administered with whey protein hydrolysates (Gaudel et al.
2013). Moreover, recent studies have shown DPP-IV inhibitory effects of bovine
casein and whey protein derived peptides (Gunnarsson et al. 2006; Tulipano et al.
2011; Nongonierma and Fitzgerald 2013). Peptides derived from β-lactoglobulin
are efficient DPP-IV inhibitors: peptide with sequence VAGTWY was able to demonstrate hypoglycaemic effects in mice in the oral glucose tolerance test (Uchida
et al. 2011). An in-silico study also showed both casein and whey proteins as precursors of DPP-IV inhibitory peptides (Lacroix and Li-Chan 2012).
Other important enzymes that play a role in insulin modulation are α-glucosidase
and α- amylase. Hence, the inhibition of these enzymes may lead to delayed carbohydrate digestion and glucose absorption may be helpful in managing diabetes
(Bharatham et al. 2008; Vankudre et al. 2015). Milk fermentation with L. bulgaricus
and L. acidophilus showed increased α-glucosidase inhibition (Apostolidis et al.
2007). In a different study, peptic digestion of whey proteins displayed high
α-glucosidase inhibition (Lacroix and Li-Chan 2013). Thus, milk derived bioactive
peptides may help in glycemic management strategy, although further work is
needed to fully determine the bioavailability of the peptides in humans.
Antihypertensive Effects
One of the major risk factors for cardiovascular disease is elevated blood pressure
(Erdmann et al. 2008). The angiotensin-I converting enzyme (ACE) helps regulate
blood pressure by catalyzing the conversion of angiotensin I to angiotensin II (a
potent vasoconstrictor) and breakdown of bradykinin (a vasodilator) (Sánchez and
Vázquez 2017). Since angiotensin II elevates the blood pressure levels, inhibiting
ACE is a way to control blood pressure (Korhonen and Pihlanto 2007). Inhibitors of
ACE are currently available in the markets to treat hypertnesio like capotril, alacepril, lisinopril and enalapril. However, their synthetic nature causes unwanted side
Nutraceutical Properties of Bioactive Peptides