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Glycemic index lowering effect of chicken solids was studied using a model system approach. Experimental samples were prepared by adding chicken powder at varying levels (10 mg, 20 mg, 30 mg, 40 mg) to 50 mg of corn starch as carbohydrate base. The chicken powder had a proximate protein content of 81.1 per cent, fat 9.1 per cent, ash 6 per cent and moisture 3.7 per cent. In vitro starch digestibility and estimated glycemic index (eGI) of the samples were estimated. It was found that only sample B and C could reduce the eGI of the sample by 22.8 per cent and 21.8 per cent respectively, with an eGI value of 68.05 and 68.9 respectively. Samples containing 30 mg and 40 mg chicken powder did not affect the eGI significantly and values were close to eGI values for the control (corn starch alone). It is concluded that chicken solids exhibit a significant (p < 0.05) glycemic index lowering effect at a level of 17 per cent to 29 per cent of the formulation, and not linearly with an increase in protein content.
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eGI Estimated glycemic index
GI Glycemic index
AUC Area under the curve
HBV High biological value
DM Diabetes mellitus
C Percentage of starch hydrolysed at time t in min
t Time (m)
C Equilibrium percentage of starch hydrolysed at 180 m
K Kinetic constant
HI Hydrolysis index
       
carbohydrate rich, low glycemic foods and should be able to
provide sustained energy release for minimum of 5 h - 6 h.
These foods must aid in preventing hypoglycaemia. Designer
foods incorporating non vegetarian ingredients have not yet
      
The addition of chicken solids to a carbohydrate base can make
the food more nutritious in terms of protein content and can
also exert a glycemic Index lowering effect, which has not
been studied extensively.
Carbohydrate constitutes the major part of Indian diets
and is considered to be the predominant factor affecting
postprandial blood glucose control1. Blood glucose response
of a food is commonly assessed using the GI2.
         
(AUC) for the blood glucose response post prandial relative
to AUC of a reference food (white bread or glucose) given
in an equivalent carbohydrate amount (50 g or 25 g)3. It is a
ranking of foods and there are three categories of GI foods-
low (GI<55), moderate (GI 55-69) and high (GI>70)4. A
low GI diet is related to be clinically useful for diabetes and
       5.
Excess intake of processed carbohydrates leads to a vicious
cycle of transient spikes in blood glucose and insulin, after
a meal trigger reactive hypoglycaemia and hunger. Repeated
consumption of a diet high in processed carbohydrates leads to
excess visceral fat, in turn increasing both, insulin resistance
    
cardio vascular diseases5.
      
type 2 DM is to achieve an optimal blood glucose control
post-prandial6. This can be achieved either by delaying the
absorption of glucose or inhibiting its uptake.
Research has shown other factors like fat, protein, GI7
and processing8       
glucose levels. Minimally processed foods increase post-
prandial glucose to a much lesser extent than the processed
foods8. Lean protein of high biological value (HBV) reduces
post-meal glucose level and also improves satiety. Nilsson9, et
al. conducted a study in healthy individuals, and reported a
decrease in post-prandial blood glucose area under the curve
approximately by 56 per cent, upon addition of whey protein to
a pure glucose drink. Thus, HBV protein foods like egg whites,
non-fat dairy protein) when consumed with meals, reduce the
post-prandial blood glucose response10.
Among the therapeutic drugs used in prevention of a high
Glycemic Index Lowering Effect of Chicken Solids on Corn Starch
Shefali Bhardwaj*, V.K. Shiby, and M.C. Pandey
Freeze Drying and Animal Products Technology Division, Defence Food Research Laboratory, Mysuru - 570011, India
Glycemic index lowering effect of chicken solids was studied using a model system approach. Experimental
samples were prepared by adding chicken powder at varying levels (10 mg, 20 mg, 30 mg, 40 mg) to 50 mg of
corn starch as carbohydrate base. The chicken powder had a proximate protein content of 81.1 per cent, fat 9.1 per
cent, ash 6 per cent and moisture 3.7 per cent. In vitro starch digestibility and estimated glycemic index (eGI) of
the samples were estimated. It was found that only sample B and C could reduce the eGI of the sample by 22.8 per
cent and 21.8 per cent respectively, with an eGI value of 68.05 and 68.9 respectively. Samples containing 30 mg and
         
a level of 17 per cent to 29 per cent of the formulation, and not linearly with an increase in protein content.
Keywords: Estimated- glycemic index; In-vitro starch digestibility; Chicken solids; Protein; Cornstarch
     
Accepted : 25 April 2017, Online published : 19 September 2017
Defence Science Journal, Vol. 67, No. 5, September 2017, pp. 518-522, DOI : 10.14429/dsj.67.11870
BHARDWAJ, et al.:     
bound enzyme at the epithelium of the small intestine
responsible for the cleavage of glucose from disaccharide) are
effective in delaying glucose absorption11,12. However, it has
      
and diarrhoea13. Some investigations related to the delay of
glucose absorption by food have been made14.
      
        
management of type 2 DM or in lowering blood glucose
levels post consumption. Researchers have reported effective
anti-diabetic compounds from natural materials15,16, like
polysaccharides from tea leaves17, hydrolysate from sardine
muscle1819, egg albumin20.
Starch digestibility varies among various carbohydrate
foods and has attracted much interest in development of low
GI foods and in the treatment of type 2 DM21. However, there
have been mixed reports on effect of protein on reduction of
glycemic index or post prandial blood glucose levels. Gullifor22,
et al. reported a decrease in the blood glucose level with a diet
consisting of 25 g carbohydrate from potato and 25 g protein
   
in the blood glucose after addition of fat was noticed. The
difference between the glycemic responses after addition of
with the carbohydrate-only diet. Papadaki23, et al. reported no
       
         
impact on GI due to its effect on the satiety, weight loss and
fat oxidation. Pineli24, et al. developed low GI quinoa milk and
suggested the GI to be lowered due to the protein content. Also,
protein is reported to have different effect on blood glucose with
or without carbohydrate, i.e. 30 mg protein with carbohydrate
affects blood glucose25 but when consumed alone, 75 g of
protein is needed to see an effect on blood glucose26.
The present study was undertaken with an aim to develop
a low GI functional food with animal protein. A model system
approach has been employed to assess the level or range within
which chicken exhibits GI lowering effect. To our knowledge,
          
within which the protein exhibits the GI lowering effect.
2.1 Materials
Corn starch and boneless chicken were procured from the
local market of Mysore, India. Boneless chicken was washed
with potable water twice and care was taken to select the lean
protein by manually removing fat before further processing.
Lean chicken was cooked, minced and dried in a hot air oven
at 60 °C - 65 °C for 5 h - 6 h. The dried chicken was ground
to a powder using a domestic mixer. The chicken powder was
stored in an airtight container till further use.
2.2 Proximate Composition
Moisture content (gravimetric method), protein (Kjedahl),
ash (incineration), fat (soxhlet method) were analysed as per
standard procedures of AOAC (1995)27.
2.3 In-vitro Starch Digestibility and estimated-
Glycemic Index
      
from A to E, where A constituted 50 mg corn starch only, B
was a mix of 50 mg corn starch +10 mg chicken powder, C was
50 mg corn starch +20 mg chicken powder, D was 50 mg corn
starch+ 30 mg chicken powder and E was 50 mg corn starch+
40 mg chicken powder.
The eGI of the products were determined according
to the methodology described by Goñi28, et al. with a few
POD glucose kit (Erba Manheim, Transasia Bio-medicals
Ltd., Solan (HP), India) and the absorbance was measured in
a UV/VIS spectrophotometer (Perkin-Elmer Lambda 40 Uv/
      
nm. Glucose was converted to starch using a multiplication
factor of 0.9. Starch digestion rate was expressed through the
percentage of starch released at each time (mg/100g sample) (0
min, 30 min, 60 min, 90 min, 120 min, 150 min, and 180 min).
( 1 )
C is percentage of starch hydrolysed at time t in minutes,
Cis the equilibrium percentage of starch hydrolysed at 180
min, and k is the kinetic constant. Every product has its own
Cand k value.
Hydrolysis curves were built (disregarding the value at
time 0), and the area under the curve (AUC) was calculated
(AUC) as per Eqn. (2):
( ) ( ) [1 ]
kt t
AUC C t t C k e
=−− −
The hydrolysis index (HI) for each sample was calculated
as the ratio between the AUC of sample and the AUC of white
39.71 (0.549 )GI HI=+×
  
2.4 Statistical Analysis
       
exponential association equation using Graphpad Prism
version 5.03 software. Anova, mean and standard deviation
were calculated using MS Excel 2010.
The prepared chicken powder was analysed for
its proximate composition (Table 1). The rate of starch
digestibility can be a determinant of the metabolic response to
a meal29. Evidences prove that slowly digested and absorbed
carbohydrates are recommended in the dietary management of
metabolic disorders, such as diabetes30
the starch digestibility rates, such as the type of starch, protein,
physical arrangement and lipids interactions, antinutrients,
  21 and food processing22. The
          
one or more reasons, mentioned earlier.
The presence of protein along with an equal amount
       
of starch in each sample, affected the starch digestibility in
         
digestibility can be accounted to the presence of peptides present
in chicken powder. Peptides have been documented to have
These enzymes are essential for breakdown of carbohydrates to
glucose in the body. Peptides from sardine muscle20 hydrolyzed
using alkaline protease were reported to have similar inhibitory
effect on the enzyme activity. Due to this inhibitory activity,
these hydrolysates can be utilised successfully in preparation of
physiologically functional food, for diabetics. Novel peptides
derived from egg white protein have been documented to have
     31 and anti-
22. It is suggested that the
    
of peptides with the enzyme21. The eGI for all samples have
been shown in Table 2, and followed the order A> E>D>C>B.
Samples B (eGI 68.05) and C (eGI 68.9) could reduce the eGI
of the sample by 22.8 per cent and 21.8 per cent respectively.
Sample D and E could reduce the eGI only by 7.6 per cent
and 4.6 per cent respectively. The reason for this decrease
is attributed to the peptides interacting with the enzymes in
The model system approach was employed to understand
the GI lowering effect of chicken solids, as no such studies
have been reported till date. This study helps to assess the level
at which it can be used in development of functional foods with
an objective to lower the post prandial blood glucose or be
low GI. We conclude that in the functional food formulation,
chicken solids at a level of 17 per cent - 29 per cent has
maximum eGI lowering effect, and can be employed in the
         
spectrum of consumers including diabetics, sports personnel
and weight watchers.
Conflict of Interest : None
1. American Diabetes Association. Approaches to
glycemic treatment. Sec. 7. In Standards of Medical
Care in Diabetesd 2015. Diabetes Care 2015, 38
  
doi: 10.2337/dc15-S010
 
in vitro starch digestibility and the glycemic index
of six different indigenous rice cultivars from the
Philippines. Food Chemistry, 2003, 83 
doi: 10.1016/S0308-8146(03)00101-8
      
glycemia, and the shape of the curve in healthy
subjects: analysis of a database of more than 1000
Figure 1. Starch digestibility curve for the samples A
to E ; Sample A: 50 mg corn starch alone,
Sample B: 50 mg corn starch + 10 mg chicken powder,
Sample C: 50 mg corn starch + 20 mg chicken powder,
Sample D: 50 mg corn starch + 30 mg chicken powder
Sample E: 50 mg corn starch + 40 mg chicken powder.
Sample C
kAUC HI(%) eGI
A 70.29 0.1015 11960 88.15 88.104
B 46.32 0.0347 7003.8 51.622 68.05
C 60.48 0.0155 7220.3 53.218 68.927
D 60.73 0.0964 10301 75.926 81.393
E 63.87 0.1203 10966 80.823 84.082
Table 2. IVSD parameters and eGI of the samples ; Sample
A: 50 mg corn starch only or 0 % chicken, Sample
B: 50 mg corn starch + 10 mg or 17 % chicken
powder, Sample C: 50 mg corn starch + 20 mg or
29% chicken powder, Sample D: 50 mg corn starch+
30 mg or 38% chicken powder, and Sample E: 50 mg
corn starch + 40 mg or 44% chicken powder
Figure 2. Percentage decrease in eGI values with increase in
protein content.
Table 1. Proximate composition of chicken powder
Component Percentage (per
Protein 81± 0.26
 9.2± 0.10
Ash 6± 0.06
Moisture 3.7 ± 0.15
BHARDWAJ, et al.:     
foods. Am J. Clin. Nutr., 2009, 89 
doi: 10.3945/ajcn.2008.26354
 
index of foods: A physiological basis for carbohydrate
exchange. Am J. Clin. Nutr.,1981, 34 
 
S. Low-glycemic index diets in the management of
diabetes: A meta-analysis of randomized controlled
trials. Diabetes Care., 2003, 26 
      
following dietary control of plasma glucose in
severely hyperglycemic obese patients. Metabolism.
1980, 29, 346-350.
doi: 10.1016/0026-0495(80)90008-6
7. Bell, K.J.; Smart, C.E.; Steil, G.M.; Brand-Miller,
and glycemic index on postprandial glucose control
in type 1 diabetes: Implications for intensive diabetes
management in the continuous glucose monitoring
era. Diabetes Care, 2015, 38 
doi: 10.2337/dc15-0100
        
Marchie, A.; Nguyen, T.H.; Wong, J.M.; de Souza,
R.; Emam, A.; Vidgen, E.; Trautwein, E.A.; Lapsley,
term effects of a plant-based dietary portfolio of
cholesterol-lowering foods on blood pressure. Eur
J. Clin. Nutr., 2008, 62(6), 781-788.
 
of amino acid mixtures and whey protein in healthy
subjects: studies using glucose-equivalent drinks.
Am. J. Clin. Nut., 2007, 85  
 
diets in diabetes management. Nutrition Metabolism,
2005, 2, 16-24.
doi: 10.1186/1743-7075-2-16
 
Effect of trestatin, an amylase inhibitor, incorporated
into bread, on glycemic responses in normal and
diabetic patients, Am. J. Clin. Nutr., 1991, 53, 61-
        
kogaku kaishi, 1996, 43, 157-163. (in Japanese).
doi: 10.1271/bbb.60.2019
13. Toeller, M. Alpha-glucosidase inhibitors in diabetes:
efficacy in NIDDM subjects. Eur. J. Clin. Invest.,1994,
24(3), 31-35.
 
Effect of trestatin, an amylase inhibitor, incorporated
into bread, on glycemic responses in normal and
diabetic patients, Am. J. Clin. Nutr., 1991, 53, 61-65.
           
alleviates advanced glycation end-product-mediated
renal injury in streptozotocin-diabetic rats. J. Food
Science, 2011, 76(7), H165-H174.
doi: 10.1111/j.1750-3841.2011.02310.x
 
and alpha-amylase inhibitoryactivities of guava
leaves. Food Chemistry, 2010, 123(1), 6-13.
doi: 10.1016/j.foodchem.2010.03.088
17. Xiao, J.; Huo, J.; Jiang, H  Yang, . Chemical
compositions and bioactivities of crude polysaccharides
from tea leaves beyond their useful date. Int. J. Bio.
Macromol., 2011, 49(5), 1143-1151.
doi: 10.1016/j.ijbiomac.2011.09.013
       
Osajima, Y. In vitro survey of alpha-glucosidase
inhibitory food components. Biosc., Biotechnol.,
Biochem., 1996, 60(12), 2019-2022.
doi: 10.1271/bbb.60.2019
       
Devahastin, S. Evaluation of bioactive compounds
and bioactivities of soybean dried by different
methods and conditions. Food Chemistry, 2011,
129(3), 899-906.
doi: 10.1016/j.foodchem.2011.05.042
    
      
  Food Chemistry, 2012,
135, 2078-2085.
doi: 10.1016/j.foodchem.2012.06.088
21. Jenkins, D.J.A.; Wolever, T.M.S.; Buckley, G.;
Lam, K.Y.; Giudici, S.; Kalmusky, J.; Jenkins, A.L.,
        
Low-glycemic-index starchy foods in the diabetic
diet. Am. J. Clin. Nut., 1988, 48, 248-254.
       
Differential effect of protein and fat ingestion on
blood glucose responses to high- and low-glycemic-
index carbohydrates in noninsulin-dependent diabetic
subjects. Am. J. Clin. Nut., 1989, 50, 773-777.
23. Papadaki, A.; Linardakis, M.; Larsen, T.M.; van
J.; Martinez, A.; Handjieva-Darlenska, T.; Holst, M.
      
effect of protein and glycemic index on children’s
body composition: The DiOGenes randomized study.
Pediatrics, 2010, 126(5), e1143-52.
doi: 10.1542/peds.2009-3633
24. Pineli, L.d.L.d.O.; Botelho, R.B.A.; Zandonadi, R.P.;
       
Teixeira, D.D.S. Low glycemic index and increased
protein content in a novel quinoa milk. LWT - Food
Sci. Technol., 2015.
doi: 10.1016/j.lwt.2015.03.094
        
P. Skipping meals or carbohydrate-free meals in
orde r t o determine ba sal insulin re quirements in
subjects with type 1 diabetes mellitus? Exp. Clin.
Endocrinol Diabetes, 2010, 118, 325-327.
doi: 10.1055/s-0029-1241199
26. Paterson, M.A.; Smart, C.E.; Lopez, P.E.; McElduff,
   
pure protein on postprandial blood glucose levels in
individuals with type 1 diabetes mellitus. Diabetic
       
Medicine, 2014, 63, 1-7.
27. AOAC. Official methods of analysis. Ed. 16th.
Washington, DC: Association of Official Analytical
Chemists, 1995.
       
starch hydrolysis procedure to estimate glycemic
index. Nutrition Research, 1997, 17(3), 427-437.
doi: 10.1016/S0271-5317(97)00010-9
          
hydrolysis in vitro as a predictor of metabolic
responses to complex carbohydrates in vivo. Am.
J. Clin. Nutr., 1981, 34, 1991-1993.
30. Jenkins, D.J.A.; Wolever, T.M.S.; Kalmusky, J.;
Giudic, S.; Giordano, C.; Wong, S.G.; Bird, J.N.;
        
Low glycemic index carbohydrate foods in the
management of hyperlipidemia. Am. J. Clin. Nutr.,
1985, 42, 604-60l7.
31. Yu, Z.; Yin, Y.; Zhao, W.; Yu, Y.; Liu, B.; Liu, J.
      
protein inhibiting alpha-glucosidase. Food Chemistry,
2011, 129, 1376-1382.
doi: 10.1016/j.foodchem.2011.05.067
Ms S. Bhardwaj       
      
Research Laboratry, Mysuru, India. She has designed the
research plan, organised the study, participated in experiments,
coordinated the data analysis, and contributed to the writing
of the manuscript.
She has designed the research plan, organised the study,
participated in experiments, coordinated the data analysis,
andcontributed to the writing of the manuscript
Dr V.K. Shiby       
Engineering. Currently she is working as a Scientist ‘D’ at
           
food product development and process modelling. She received
DRDO Laboratory Acientist Award (2013).
She has participated in the experimental design, organisedthe reported
study and contributed to the writing of themanuscript.
Dr M.C. Pandey received his PhD in Agriculture Engineering.
           
area of agriculture and food engineering.
He contributed towards the experimental design, organised
thestudy and drafting of the manuscript.
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Aim To determine the effects of protein alone (independent of fat and carbohydrate) on postprandial glycaemia in individuals with Type 1 diabetes mellitus using intensive insulin therapy. Methods Participants with Type 1 diabetes mellitus aged 7–40 years consumed six 150 ml whey isolate protein drinks [0 g (control), 12.5, 25, 50, 75 and 100] and two 150 ml glucose drinks (10 and 20 g) without insulin, in randomized order over 8 days, 4 h after the evening meal. Continuous glucose monitoring was used to assess postprandial glycaemia.
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BACKGROUND: Continuous glucose monitoring highlights the complexity of postprandial glucose patterns present in type 1 diabetes and points to the limitations of current approaches to mealtime insulin dosing based primarily on carbohydrate counting. METHODS: A systematic review of all relevant biomedical databases, including MEDLINE, Embase, CINAHL, and the Cochrane Central Register of Controlled Trials, was conducted to identify research on the effects of dietary fat, protein, and glycemic index (GI) on acute postprandial glucose control in type 1 diabetes and prandial insulin dosing strategies for these dietary factors. RESULTS: All studies examining the effect of fat (n = 7), protein (n = 7), and GI (n = 7) indicated that these dietary factors modify postprandial glycemia. Late postprandial hyperglycemia was the predominant effect of dietary fat; however, in some studies, glucose concentrations were reduced in the first 2–3 h, possibly due to delayed gastric emptying. Ten studies examining insulin bolus dose and delivery patterns required for high-fat and/or high-protein meals were identified. Because of methodological differences and limitations in experimental design, study findings were inconsistent regarding optimal bolus delivery pattern; however, the studies indicated that high-fat/protein meals require more insulin than lower-fat/protein meals with identical carbohydrate content. CONCLUSIONS: These studies have important implications for clinical practice and patient education and point to the need for research focused on the development of new insulin dosing algorithms based on meal composition rather than on carbohydrate content alone.
The objectives of this study were to identify novel peptides from albumin, and to evaluate and validate the anti-diabetic activity of peptides against α-glucosidase and α-amylase. In the research, albumin hydrolysate was purified and identified, tandem MS was adapted to characterise the amino acid sequences of peptides from the hydrolysate. In addition, anti-diabetic effects of the peptides with α-glucosidase and α-amylase inhibitory activity have been performed. The present work found eight novel peptides from albumin. Results also suggested that peptide KLPGF had α-glucosidase inhibitory activity with an IC(50) of 59.5±5.7μmoll(-1) and α-amylase inhibitory activity with an IC(50) of 120.0±4.0μmoll(-1). In conclusion, the results revealed that the peptide KLPGF was a potential anti-diabetic inhibitor.
The 75% ethanol extract from guava (Psidium guajava Linn.) leaves was extracted further, in turn, with CH2Cl2, EtOAc and n-BuOH to afford four fractions, CH2Cl2-soluble, EtOAc-soluble, n-BuOH-soluble and residual extract fractions. Both the n-BuOH-soluble and EtOAc-soluble fractions showed high inhibitory activity against α-glucosidase and α-amylase. Seven pure flavonoid compounds, quercetin (1), kaempferol (2), guaijaverin (3), avicularin (4), myricetin (5), hyperin (6) and apigenin (7), were isolated (using enzyme assay-guide fractionation method) from the n-BuOH-soluble and EtOAc-soluble fractions. The structures of these pure compounds were determined on the basis of MS and NMR data and the activities of these compounds were evaluated. Compounds 1, 2 and 5 showed high inhibitory activities, with IC50 values of 3.5 mM, 5.2 mM and 3.0 mM against sucrase, with IC50 values of 4.8 mM, 5.6 mM and 4.1 mM against maltase and with IC50 values of 4.8 mM, 5.3 mM and 4.3 mM against α-amylase, respectively. We found that myricetin showed the most powerful activity among these compounds with a 70% inhibition against sucrase at a concentration of 1.5 mg/ml. The hydroxyl group at the 3-position on the A-ring and a number of hydroxyl groups attached to the C-ring played important roles in the inhibition activity. There was an obvious synergistic effect (the mixing action of two compounds) against α-glucosidase, but against α-amylase this was not found. This is the first study of the active compositions of guava leaves and the biological activity of the active compositions against α-glucosidase and α-amylase.
Soybean has attracted significant research and commercial interests due to its many health-promoting bioactive compounds, especially isoflavones (beta-glucosides, malonyl-beta-glucosides, acetyl-beta-glucosides and aglycones). Isoflavones possess antioxidant activity and alpha-glucosidase inhibitory activity, which has proved effective in the treatment of type 2 diabetes mellitus. Prior to its use, however, soybean needs to be dried to extend its storage life and to prepare the material for subsequent food or pharmaceutical processing. The present study investigated the effects of drying methods and conditions on the drying characteristics, isoflavones, antioxidant activity and alpha -glucosidase inhibitory activity of dried soybean. Hot-air fluidized bed drying (HAFBD), superheated-steam fluidized bed drying (SSFBD) and gas-fired infrared combined with hot air vibrating drying (GFIR-HAVD) were carried out at various drying temperatures (50, 70, 130 and 150 degrees C). The results showed that higher drying temperatures led to higher drying rates and higher levels of beta-glucosides and antioxidant activity, but to lower levels of malonyl-beta-glucosides, acetyl-beta-glucosides and total isoflavones. At the same drying temperature GFIR-HAVD resulted in the highest drying rates and the highest levels of beta-glucosides, aglycones and total isoflavones, antioxidant activity as well as alpha-glucosidase inhibitory activity of dried soybean. A drying temperature of 130 C gave the highest levels of aglycones and alpha-glucosidase inhibitory activity in all cases. The relationships between all the studied parameters were monitored and simple correlations between them were determined.
An in vitro procedure to measure the rate of starch digestion in starchy common foodstuffs was developed. A first-order equation that rules the hydrolytic process was found: CC∞ (1−e−kt). Besides an in vivo assay, to calculate the glycemic index (GI), was carried out on thirty healthy volunteers. This is a simple in vitro method that could be used to estimate the metabolic glycemic response to a food. The best correlated value with in vivo glycemic responses was the percentage of starch hydrolysis at 90 min (r= 0.909, p≤0.05, GI1 = 39.21 + 0.803(H90)).
Angelica acutiloba root, a Japanese species of Dong quai being cultivated in Hualien County in eastern Taiwan, is used primarily for gynecological disorders in women. Increasing evidence indicates that advanced glycation end-products (AGEs) contribute to the pathogenesis of diabetic nephropathy. We investigated whether A. acutiloba root is beneficial in the amelioration of AGE-mediated renal injury in a diabetic rat model. Streptozotocin (STZ)-diabetic rats were treated orally with A. acutiloba root extract (AARE) [50, 100, 200 mg/(kg × day)] for 8 wk. Changes in renal function-related parameters in plasma and urine were analyzed at the end of the study. Kidneys were isolated for enzyme immunoassay, pathology histology, immunohistochemistry, and Western blot analyses. Polyphenolic compounds and flavonoids were abundant in AARE. AARE [200 mg/(kg × day)] partially decreased the high plasma glucose level in diabetic rats. Diabetic-dependent alterations in urinary albumin, 24-h urinary albumin excretion rate, creatinine clearance, and glomerular mesangial matrix expansion were ameliorated by AARE treatment. The increased expression of nuclear factor-κB, transforming growth factor-β(1), and the progressive accumulation of fibronectin in kidney of diabetic rats were attenuated by AARE treatment. AARE treatment ameliorated the elevated levels of advanced glycation end products (AGEs) and mitochondrial thiobarbituric acid-reactive substance, as well as the elevated levels of Nε-(carboxymethyl)lysine and receptors for AGEs in kidneys of diabetic rats. The results show that A. acutiloba root has an anti-diabetic property that involves antihyperglycemia accompanied by amelioration of glycation-mediated renal damage.
The chemical compositions and bioactivities of crude tea polysaccharides (TPS) from the out-of-date tea leaves (beyond their useful date), namely Xihu Longjing (XTPS), Anxi Tieguanyin (TTPS), Chawentianxia (CTPS) and Huizhoulvcha (HTPS), in market were investigated. These TPS showed similar neutral sugar content and different distribution of molecular weight (1-800 kD). These crude TPS were mainly composed of rhamnose, arabinose, galactose, glucose, xylose, mannose, and galacturonic acid. IR spectra confirmed that these crude TPS were composed of polysaccharide, protein and uronic acids. These TPS showed similar DPPH scavenging activity and exhibited lower DPPH scavenging activities than Vc within 25-200 μg/mL. However, these TPS with higher concentrations (200-400 μg/mL) showed similar DPPH scavenging activity with Vc. HTPS exhibited significant higher superoxide anion scavenging activity than others TPS and gallic acid. XTPS showed significant higher inhibitory effects on α-glucosidase and α-amylase with inhibitory percentages of 64.35% and 82.24% than others TPS. TTPS, XTPS, and HTPS exhibited similar inhibition ability on α-d-glucosidase and α-amylase. The overdue tea leaves can be a resource of tea polysaccharides as function food.