Livestock Research for Rural Development 19 (11) 2007 Guide for preparation of papers LRRD News

Citation of this paper

Comparative evaluation of protein quality of raw and differentially processed seeds of an under-utilized food legume, Abrus precatorius L.

M Pugalenthi*, V Vadivel and P Janaki

Department of Biotechnology, Karpagam Arts and Science College,
Coimbatore - 641 021, Tamil Nadu, India
pugalmuthiah@rediffmail.com

Abstract

In the present study, the nutritional and antinutritional characteristics, biological value and protein quality of raw and differentially processed seed samples of a South Indian under-utilized food legume, Abrus precatorius L. were investigated.

 

The mature seeds were found to contain 21.99% of protein, 8.9% of lipid, 6.4% of fiber, 5.3% of ash and 57.3% of carbohydrates. Although, various antinutritional compounds were present in the raw seeds, the autoclaving treatment effectively reduced their maximum levels without affecting the nutritional value of Abrus precatorius seeds. When considering the biological value, the rats fed on autoclaved seeds exhibit better growth performance such as higher feed intake (FI) (239g) and body weight gain (BWG) (67.4g). Moreover, the protein quality parameters such as protein efficiency ratio (PER), true digestibility (TD), biological value (BV), net protein utilization (NPU) and utilizable proteins (UP) of Abrus precatorius seeds were also significantly improved by autoclaving treatment when compared to other processing methods such as soaking, cooking and roasting.

Key words: Abrus precatorius, antinutritional compounds, biological value, processing methods, protein quality


Introduction

The recent research trends indicate that there is an increase interest towards the search for alternative/additional protein source to meet the increasing requirements for protein source for expanding livestock industries, especially in the developing countries (Janardhanan et al 2003). The food scientists and nutritionists have attempted to develop certain novel, alternative protein sources mainly due to two main reasons:  (i) the low production of oil seeds and grain legumes;  and (ii) the stiff competition between man and the livestock industries in utilizing the existing legume seeds as protein source.

 

Even though soy bean and other common legume grains plays a key role as protein source for both human beings and animals, their production is not sufficient to meet the protein requirements of increasing population and expanding livestock industries (Vijayakumari et al 2007). The heavy demand for these common legumes has given rise to a disproportionate increase in their prices, and consequently, the cost of the food and feedstuffs. Hence, the recent research efforts have directed to identify and evaluate the under-utilized legume seeds as alternative/additional protein source for the future world (Janardhanan et al 2003; Pugalenthi et al 2005).

 

In this context, the seeds of Abrus precatorius L., an under-utilized food legume widely distributed through out the tropics and Andaman Islands, having good nutritional properties receives more attention as an alternative protein source. The seeds were reported to contain appreciable amount of protein (16-23%) with major proportion of albumin proteins, has a balanced amino acid composition and high content of lipid (2.0-9.4%) and desirable mineral composition (Rajaram and Janardhanan 1992; Mohan and Janardhanan 1995; Banerji and Dixit 1998; Vadivel and Janardhanan 1999). The cooked seeds have been consumed by Onges of Andaman and Katkharis of Pune District, Maharastra, India (Janardhanan et al 2003).

 

The exploitation and development of such potential non-conventional legume seeds as protein source for human beings/animals may offer a good scope to meet the increasing protein requirements at large, particularly in the developing countries. However, before recommending such indigenous foodstuffs, their nutritional properties and biological value should be thoroughly investigated. Although reports are available on the biochemical composition and nutritional value of Abrus precatorius, the information regarding the biological value of seed proteins appears to be meager. Hence, in the present study an attempt has been made to analyze the biological value and protein quality of raw and differentially processed seeds of Abrus precatorius collected from South India.

 


Materials and methods

 

Seed sample

 

The seed materials of Abrus precatorius L. were collected from Anaimalai Hills, Pollachi, Coimbatore District, Tamil Nadu, South India. Soon after collection, the immature and damaged seeds were removed and the mature seeds were dried in the sun light for 24 h and stored in plastic containers in refrigerator (5oC), until further use.

 

Processing methods

 

Five separate batches of whole seeds of Abrus precatorius were taken and the first batch was soaked in distilled water for 6 h at room temperature (30 ± 2oC) in the bean to water ratio of 1:10 (w/v). The second batch of seeds was cooked at 90-95oC for 1 h in the bean to water ratio of 1:10 (w/v). The third batch of seeds was taken in the bean to water ratio of 1:10 (w/v) in a metal container and autoclaved at 15 lb pressure (121oC) for 30 min. The fourth batch seeds was roasted for 30 min at 100-110oC in an iron pot along with clean fine sand to prevent the burning of the seed coat and to ensure the uniform distribution of heat. After each treatment, the treated seeds were rinsed with distilled water, separately, and then dried at 55oC for 6 h in a hot air oven. The fifth batch of raw seeds was stored as such without any treatment. 

 

Analytical methods

 

All the processed as well as raw seeds of separate batches were powdered in a Willey Mill to 60-mesh size and the powdered samples were used for further analysis. The proximate composition such as moisture, crude protein, crude lipid, crude fiber and ash content of raw as well as processed seed flour was determined by following AOAC (1990) method. Nitrogen free extractives (NFE) and calorific value were calculated by following the method of Siddhuraju et al (1992).

 

The antinutritional compounds such as total free phenolics and tannin content of raw and processed seed samples were extracted and estimated by following the method of Sadasivam and Manickam (1992) and Burns (1971), respectively. The L-Dopa (L-3,4-Dihydroxyphenylalanine) content was quantified according to the method of Brain (1976), whereas, the phytic acid content was determined by following the method of Wheeler and Ferrel (1971) and the oligosaccharides content was estimated by following Pugalenthi et al (2006) method. The haemagglutinating activity was analyzed according to the method of Makker et al (1997) and trypsin inhibitor activity was determined by casein digestion method (Mulimani and Vadiraj 1993) while α- amylase inhibitor activity was measured according to the method  of Mulimani and Rudrappa (1994).

 

Biological evaluation of protein quality

 

Fifty numbers of 23 days old male albino rats with an initial body weight of 40 ± 5 g were equally divided into five groups with 10 animals in each group and housed individually in cages. The animals were maintained at 22oC with 12 h light and 12 h dark at Karpagam Animal House (Approved by Animal Ethical Committee, Government of India). The experimental diets were prepared according to the method of Chapman et al (1959) by including corn starch (80%), corn oil (10%), non-nutritive cellulose (5%), mineral mixture (4%) and vitamin mixture (1%). The test diets were prepared by incorporating raw and differentially processed seeds as protein source at 10% level in the diet and the control diet was prepared by incorporating casein as a protein source. The control and test diets were fed to respective animal groups along with water ad libitum for 28 days and the growth performance of the experimental animals were analyzed.

 

Feed Intake (FI): Dry feed fed (g)/animal/28 days

Body Weight Gain =

Final body weight, g – Initial body weight, g

x 100

Initial body weight, g

The protein content of the diet was determined by micro-Kjeldahl method (AOAC 1990) and Feed Efficiency Ratio (FER) and Protein Efficiency Ratio (PER) were calculated according to the method of Chapman et al (1959).

Feed Efficiency Ratio =

Body weight gain, g

Dry feed consumed, g

Protein Efficiency Ratio =

Body weight gain, g

Protein consumed, g

The nitrogen balance studies were conducted for 14 days with 60 numbers of male albino rats of 50 ± 5 g body weight. The rats were randomly separated into six groups with 10 animals in each group and individually housed in polypropylene metabolic cages. The animal groups were fed with control casein diet, raw and differentially processed seeds included test diets separately and one batch was also fed with protein free basal diet for the determination of endogenous and metabolic nitrogen loss in faeces and urine. After 9 days of acclimatization period, the urine and faeces of the experimental animals were collected for five days and pooled separately. The nitrogen content of the urine and faeces were estimated by micro-kjeldahl method (AOAC 1990) and the values of True Digestibility (TD) and Biological Value (BV) of seed proteins were determined by following the method of Chick et al (1935) and Net Protein Utilization (NPU) by Platt et al (1961), whereas, the level of Utilizable Proteins (UP) was calculated by Gupta et al (1979) method.

True Digestibility =

NI – (NF1 – NF2)

x 100

NI

Biological Value =

NI – (NF1 – NF2) – (NU1 – NU2)

x 100

NI – (NF1 – NF2)

Net Protein Utilization =

NI – (NF1 – NF2) – (NU1 – NU2)

x 100

NI

Where,

NI = Nitrogen intake of the animals.

NF1= Nitrogen excreted in the faeces of the animals fed with test diet.

NF2= Nitrogen excreted in the faeces of the animals fed with protein free diet.

NU1= Nitrogen excreted in the urine of the animals fed with test diet.

NU2= Nitrogen excreted in the urine of the animals fed with protein free diet.

 

Statistical analysis

 

Results were expressed as mean values ± standard deviations of three separate determinations. The data was subjected to a one-way analysis of variance (ANOVA) and the significance of difference between means at 5% was determined by Duncan’s Multiple Range Test (DMRT) using Irristat software (version 3/93).

 


Results and discussion

 

Proximate composition

 

The proximate composition of raw and processed seeds of Abrus precatorius were shown in Table 1.


Table 1.  Proximate composition of raw and differentially processed seeds of Abrus  precatorius

Proximate composition

Raw seeds

Processed seeds

Soaked

seeds

Cooked

seeds

Autoclaved

seeds

Roasted

seeds

Moisture, %

6.140c ± 0.24

6.220e ± 0.15

6.160d ± 0.04

6.090b ± 0.12

5.630a ± 0.20

Crude protein1

21.99d ± 0.31

21.84a ± 0.25

21.93b ± 0.17

22.04e ± 0.25

21.95c ± 0.12

Crude lipid1

8.940c ± 0.22

8.920b ± 0.08

8.940c ± 0.24

8.950d ± 0.20

8.900a ± 0.15

Crude fiber1

6.430e ± 0.17

6.320b ± 0.25

6.380d ± 0.13

6.360c ± 0.22

6.140a ± 0.32

Ash1

5.330e ± 0.25

4.580a ± 0.25

4.930b ± 0.30

5.170c ± 0.25

5.320d ± 0.20

Nitrogen Free Extractives %

57.31a ± 0.02

58.34e ± 0.25

57.82d ± 0.12

57.48b ± 0.10

57.69c ± 0.17

Calorific value, kJ / 100 g DM

1661a ± 0.14

1674e ± 0.05

1668d ± 0.13

1665c ± 0.06

1664b ± 0.22

Values are mean and standard deviation of three separate determinations.

Values in the same row with different roman superscript are significantly different (p<0.05).

1Values expressed on g/100g sample dry matter basis


The crude protein and lipid content of raw seeds (21.99% & 8.94%) were found to be similar when compared to certain common legumes such as Pisum sativum (21.9% & 2.34%); Phaseolus vulgaris (20.9% & 2.49%); Cicer arietinum (18.5% & 6.69%) and Lens culinaris (20.6% & 2.15%) as reported by Costa et al (2006). The protein and lipid content of autoclaved seed samples (22.04% & 8.95%) were higher than the raw and other processed seeds, which was in consonance with the earlier report in velvet beans (Siddhuraju and Becker 2005; Vadivel and Pugalenthi 2007). The reduction of the ash content in the soaked seeds (14%) when compared to raw seed samples might be due to the leaching of both micro and macro minerals into the soaking medium through the enhanced permeability of the seed coats during soaking treatment.

 

Antinutritional compounds

 

The effect of various processing methods such as soaking, cooking, autoclaving and roasting on the levels of antinutritional compounds of Abrus precatorius were given in Table 2.


Table 2.  Effect of various processing methods on the antinutritional compounds of Abrus precatorius seeds

 

Antinutritional compounds

 

Raw seeds

Processed seeds

Soaked

seeds

Cooked

seeds

Autoclaved

seeds

Roasted

seeds

Total free phenolics1

1.060e ± 0.13

0.960d ±0.26

0.830b ± 0.02

0.290a ± 0.01

0.910c ± 0.21

Tannins1

0.530e ± 0.12

0.470d ± 0.01

0.270b ± 0.01

0.140a ± 0.02

0.420c ± 0.13

L- Dopa1

2.030e ± 0.02

1.250d ± 0.02

0.950c ± 0.02

0.320a ± 0.03

0.820b ± 0.31

Phytic acid1

0.930e ± 0.23

0.850d ± 0.02

0.560b ± 0.02

0.260a ± 0.05

0.630c ± 0.06

Raffinose1

1.230e ± 0.14

1.108c ± 0.12

0.820b ± 0.17

0.340a ± 0.01

1.110d ± 0.08

Stachyose1

1.490e ± 0.19

1.140d ± 0.15

0.860b ± 0.02

0.630a ± 0.04

0.910c ± 0.13

Verbascose1

2.330e ± 0.15

1.570d ± 0.43

1.220c ± 0.32

0.760a ± 0.12

1.180b ± 0.15

Haemagglutinating activity2

34.86e ± 1.41

25.41d ± 1.25

22.76c ± 1.07

9.640a ± 0.15

20.19b ± 0.18

Trypsin inhibitor activity3

41.33e ± 1.52

36.41d ± 2.36

25.02c ± 0.85

14.50a ± 1.04

22.30b ± 1.32

Amylase inhibitors activity4

26.01e ± 0.71

24.26d ± 0.95

17.51b ± 0.73

10.30a ± 0.66

23.12c ± 1.24

Values are mean and standard deviation of three separate determinations.

Values in the same row with different roman superscript are significantly different (p<0.05).

1Values expressed on g/100g sample dry matter basis.

2HU- Haemagglutinating unit / g sample

3TIU- Trypsin inhibitor unit / g sample

4AIU- Amylase inhibitor unit / g sample


Among the various processing methods employed, the autoclaving was found to significantly (p<0.05) reduce the maximum levels of various antinutritional substances such as total free phenolics (72%), tannins (73%), L-Dopa (84%), phytic acid (72%), oligosaccharides like raffinose (72%), stachyose (57%) and verbascose (67%), haemagglutinating activity (72%), trypsin inhibitor activity (65%) and amylase inhibitor activity (60%). Similarly, significant reduction of various antinutritional compounds during autoclaving treatment was reported for several under-utilized legumes like Bauhinia purpurea (Vijayakumari et al 2007); Dolichos lablab (Vijayakumari et al 1995); Mucuna monosperma (Vijayakumari et al 1996); Vigna aconitifolia and Vigna sinensis (Vijayakumari et al 1998).

 

Growth performance of the animals

 

The growth performance of the experimental animals fed with diets containing raw and processed Abrus precatorius seeds was illustrated in Table 3.


Table 3.  Growth performance of experimental animals and Protein Efficiency Ratio (PER) of raw and processed seeds of Abrus precatorius

 

Experimental animals

Growth Performance of the experimental animals

Feed Intake, 
g/28 days

Body Weight Gain,
g/28 days

Feed Efficiency
Ratio

Protein Efficiency

Ratio

Control group animals1

292.64f ± 0.23

96.29f ± 0.54

0.33e ± 0.17

3.32f ± 0.62

Test group animals2

161.43a ± 1.34

31.62a ± 2.16

0.19a ± 0.03

1.97a ± 0.91

Test Group animals3

194.02b ± 0.34

40.15b ± 0.18

0.20b ± 0.09

2.11c ± 0.52

Test Group animals4

206.74c ± 3.12

53.38d ± 0.12

0.25c ± 0.06

2.54d ± 0.11

Test Group animals5

229.16e ± 0.41

68.24e ± 0.67

0.29d ± 0.02

2.96e ± 0.27

Test Group animals6

212.51d ± 1.53

41.77c ± 0.14

0.19a ± 0.02

1.98b ± 0.31

Values are mean and standard deviation of three separate determinations.

Values in the same column with different roman superscript are significantly different (p<0.05).

1Fed with casein diet; 2Fed with raw Abrus precatorius diet; 3Fed with soaked Abrus precatorius diet; 4Fed with cooked Abrus precatorius diet; 5Fed with autoclaved Abrus precatorius diet; 6Fed with roasted Abrus precatorius diet


The FI value of the animals fed with diet containing raw seeds (161 g) was significantly lower (p<0.05) as compared to casein (292 g) and treated seeds (194-229 g) and earlier reports on Canavalia ensiformis (225 g) and Canavalia gladiata (244 g) (Bressani et al 1987), but higher than the vegetable peas (105-120 g) (Saharan and Khetarpaul 1994) and Canavalia maritima (93 g) (Seena et al 2005). The notable difference in the FI value of the rats fed with diet containing raw and differentially processed Abrus precatorius seeds was probably due to the difference between the diets in protein quality and levels of antinutritional compounds of the incorporated seeds. Maximum reduction on the levels of various antinutritional substances under autoclaving treatment might be related to larger FI values (229 g) of animals fed with autoclaved Abrus precatorius seeds inclusive diet.

 

The animal group fed with raw Abrus precatorius seeds included diet shows lowest BWG value (31.6 g) when compared to the control (96 g) and test animals fed with diet included with treated seeds (40-68 g). The BWG value of animals fed with diet containing raw seeds of the present study was in agreement with an earlier report on vegetable peas (23-28 g) (Saharan and Khetarpaul 1994). Among the different treated seeds, the autoclaved seeds significantly improve the BWG of rats (68 g), which was higher than the BWG values for pressure-cooked seeds of Canavalia ensiformis (28 g) and Canavalia gladiata (32 g) (Bressani et al 1987). Soaking and cooking processing methods were not demonstrated to have a beneficial effect on the growth rate of the animals. It might be due to the presence of heat resistant antinutritional compounds in the Abrus precatorius seeds, which are not destroyed completely by the soaking and cooking treatments.

 

The raw Abrus precatorius seeds exhibit poor FER (0.19) and PER (1.97) values when compared to control and processed seeds (Table 3), which might be due to the presence of high concentration of antinutritional substances and poor quality of proteins of the raw seeds. However, the FER and PER values of raw Abrus precatorius seeds were found to be higher than the faba beans (0.032 & 0.32) (Gupta et al 2005), but lower than vegetable peas (0.22 & 2.17) (Saharan and Khetarpaul 1994). Among the different treatments, the autoclaving resulted in significant (p<0.05) improvement of FER (0.29) and PER (2.96) of Abrus precatorius seeds. The PER value of autoclaved Abrus precatorius seed was higher when compared to Canavalia ensiformis (1.24) and Canavalia gladiata (1.24) (Bressani et al 1987). The results observed from the present study showed that the higher the FI, the higher the PER values obtained, which was coincided with an earlier report given by Bender (1956), in which he has pointed out that the PER determination is depends upon feed consumption.

 

The raw as well as processed seeds of Abrus precatorius exhibited lower PER values when compared to control casein diet. Usually much of the sulphur containing amino acids such as cysteine and methionine supplied in the diet were used to synthesize pancreatic enzymes (Fernandez et al 1996). This exacerbated the deficiency of sulphur containing amino acids in the legume seeds and manifested a lower production of body tissues. Rerouting of retained nitrogen in the animal group fed with raw Abrus precatorius seeds containing diet may explain why PER in this group was significantly lower than in control, despite the fact that protein content was similar among these groups.

 

Among the processed seeds, the soaked and cooked seeds were exhibited lower PER values (1.97 and 2.11, respectively), which might be due to the fact that soaking and cooking treatments are not effective in reducing the antinutritional compounds, which interfere with the protein quality of Abrus precatorius seeds. The lower PER value of roasted (1.98) seeds compared to casein (3.32) and autoclaved seeds (2.96) could be due to the fact that heat accelerates the millard reaction and makes the protein unavailable for digestion (Sagarbieri 1989). According to Friedman (1996), PER value below 1.5 describes a protein of poor quality; between 1.5 and 2.0 an intermediate quality and above 2.0 good quality. Hence, the seed proteins of raw Abrus precatorius was considered as intermediate quality seed proteins, whereas, the processed seeds possess proteins with good quality.

 

Protein quality

 

The protein quality such as True Digestibility (TD), Biological Value (BV), Net Protein Utilization (NPU) and Utilizable Proteins (UP) of raw and processed Abrus precatorius seeds were presented in Table 4.


Table 4.  Protein quality of raw and processed seeds of Abrus precatorius

Experimental animals

Protein quality of Abrus precatorius seeds

True Digestibility, %

Biological Value, %

Net Protein Utilization, %

Utilizable Proteins,  %

Control group animals1

92.47f ± 0.18

82.53f ± 0.21

73.65f ± 0.21

60.38f ± 0.19

Test group animals2

65.24a ± 0.32

58.27a ± 0.23

42.83a ± 0.15

10.27a ± 0.16

Test Group animals3

69.56b ± 0.31

62.44b ± 0.15

46.29c ± 0.13

11.65b ± 0.14

Test Group animals4

72.81d ± 0.13

65.26d ± 0.02

49.56d ± 0.15

14.42d ± 0.16

Test Group animals5

78.35e ± 0.12

70.51e ± 0.31

56.48e ± 0.21

19.16e ± 0.62

Test Group animals6

71.13c ± 0.24

63.49c ± 0.12

44.24b ± 0.14

13.08c ± 0.15

Values are mean and standard deviation of three separate determinations.

Values in the same column with different roman superscript are significantly different (p<0.05).

1Fed with casein diet; 2Fed with raw Abrus precatorius diet; 3Fed with soaked Abrus precatorius diet; 4Fed with cooked Abrus precatorius diet; 5Fed with autoclaved Abrus precatorius diet; 6Fed with roasted Abrus precatorius diet


The TD value of raw seeds was found to be lower (65%) when compared to control (92%) and treated seeds (69-78%) of the present study, but higher when compared to the TD value of Canavalia maritima (42.2%) (Seena et al 2005); Vicia faba (63.4%) (Gupta et al 2005); Bauhinia purpurea (46.4%) (Vijayakumari et al 1997) and comparable with vegetable peas (65.8-66.7%) (Saharan and Khetarpaul 1994). The autoclaving treatment significantly improved the TD level of Abrus precatorius (78%), which was higher than the values reported for Canavalia ensiformis (76.4%) (Bressani et al 1987) and Vicia faba (71.4%) (Gupta et al 2005).

 

The consumption of raw legume seed proteins was reported to increases the endogenous nitrogen loss through the shedding of intestinal mucosa (Sanoja and Bender 1983; Fairweather-Tait et al 1983), an effect that reduces the biological value of raw legume seed proteins. Further, the presence of various antinutritional substances, including trypsin inhibitors, which inhibits the complete digestion of protein and increases the excretion of endogenous faecal nitrogen (Nestares et al 1996) was also partly responsible for the decrease in the TD value of seed proteins of raw Abrus precatorius seeds.

 

Among the differentially treated seeds, lowest BV value was recorded for raw Abrus precatorius seeds (58%), which was lower than that of BV level of vegetable peas (62.9-63.1%) (Saharan and Khetarpaul 1994) and faba bean (60.4%) (Gupta et al 2005), but comparable with Bauhinia purpurea (57.2%) (Vijayakumari et al 1997). The NPU value of raw Abrus precatorius seeds was also lower (42.8%) when compared to casein (73.6%) and differentially treated seeds (46.2-56.4%), but similar with that of an earlier reports on vegetable peas (41-42%) (Saharan and Khetarpaul 1994) but higher than Canavalia maritima (16.8%) (Seena et al 2005) and Vicia faba (38.3%) (Gupta et al 2005). The autoclaved seeds exhibited highest level of NPU (56.4%) among the raw and different treated seeds, which was also higher than the previous report on Bauhinia purpurea (46.4%) (Vijayakumari et al 1997). The level of UP of raw Abrus precatorius seeds (10.2%) was higher than that of vegetable peas (8.4-8.6%) (Saharan and Khetarpaul 1994) and Bauhinia purpurea (7.2%) (Vijayakumari et al 1997). The highest level of UP (19.1%) was registered by autoclaved seeds when compared to raw and other processed seeds (10.2-19.1%).

 

Rats that received dietary casein as protein source were able to take full advantage of the nitrogen they retained to favour growth, probably as a result of the more balanced supply of amino acids provided by this diet. In rats fed with raw Abrus precatorius seeds, part of the nitrogen retained may have been rerouted for the synthesis of digestive enzymes such as trypsin and chymotrypsin (Liener 1994) to offset the effects of various antimetabolic substances present in the raw seeds, hence the seed proteins of raw Abrus precatorius seeds obtain poor TD, BV, NPU and UP values.

 

The protein quality parameters such as TD, BV, NPU and UP of the autoclaved Abrus precatorius seeds were higher than the raw and other processed seeds, which was in consonance with the previous study in Bauhinia purpurea (Vijayakumari et al 1997) and Vigna unguiculata (Dario and Salgado 1994). The decrease in the trypsin inhibitor activity and other antinutritional constituents as a consequence of autoclaving treatment would have been reducing the faecal nitrogen excretion in rats fed with autoclaved seeds included diet. Improvement in the protein quality after autoclaving treatment might be attributed to reduction on the levels of various antinutrients in addition to some other factors such as disruption of protein structure and increased accessibility of the seed proteins to enzymatic attack (Nielson 1991).

 

The fact that no such decrease in faecal nitrogen excretion was occurred in the rats fed with diet containing roasted seeds may have been due to the fact that dry heat treatment cause isopeptide formation (Dutson and Orcutt 1984; Kirk 1984). This reduces the protein quality, as isopeptides are not hydrolyzed in the intestine, are resistant to proteolytic enzymes and are thus excreted in faeces. As a result, digestibility and availability of some amino acids are reduced (Kirk 1984) and thus gave poor values of BV, NPU and UP for roasted gila bean seeds. Geervani and Theophilus (1980) also observed that wet heat processing method improves the protein quality of Cicer arietinum and Vigna radiata to a greater extent than dry heat methods.


Conclusions


Acknowledgements

Authors are grateful to the University Grants Commission for giving financial support to a Major Research Project [Sanction No. F. 3 – 42/2004 (SR) dt. 12.01.2004] and thankful to the Management and Administrative authorities of Karpagam Arts and Science College for their encouragement and support.

 


References

 

AOAC 1990 Official methods of analysis, 15th edition. Association of Official Analytical Chemists, Washington, DC.

 

Banerjee R and Dixit B S 1988 Potential under-exploited minor oilseeds resources for oil-based industries. Applied Botanical Abstracts 18, 134-150

 

Bender A E 1956 Relation between protein efficiency and net protein utilization. British Journal of Nutrition 10, 135-143

 

Brain K R 1976 Accumulation of L- Dopa in cultures from Mucuna pruriens. Plant Science Letters 7, 157-161

 

Bressani R, Gomez B R, Garcia A and Elias L G 1987 Chemical composition, amino acid content and protein quality of Canavalia seeds. Journal of Science of Food and Agriculture 40, 17-23

 

Burns R R 1971 Methods for estimation of tannin in grain, Sorghum. Agronomic Journal 63, 511-512

 

Chapman D G, Castillo R and Campbell J A 1959 Evaluation of proteins in foods. Canadian Journal of Biochemistry and Physiology 37, 679-683

 

Chick M, Hutchinson J C D and Jackson M M 1935 The biological value of proteins. 6: Further investigation of balance sheet method. Biochemistry Journal 29, 1702-1711

 

Costa G E A, Queiroz-Monici K S, Machado Reis S M P and Oliveira A C 2006 Chemical composition, dietary fiber and resistant starch contents of raw and cooked pea, common bean, chickpea and lentil legumes. Food Chemistry 94, 327-330

 

Dario A C and Salgado J M 1994 Effect of thermal treatments on the chemical and biological value of irradiated and non-irradiated cowpea (Vigna unguiculata L. Walp) flour. Plant Foods for Human Nutrition 46, 181-186

 

Dutson T R and Orcutt M W 1984 Chemical changes in proteins produced by thermal processing. Journal of Chemical Education 61, 303-307

 

Fairweather-Tait S J, Gee J M and Johnson I T 1983 The influence of cooked kidney beans (Phaseolus vulgaris) on intestinal turnover and faecal nitrogen excretion in rats. British Journal of Nutrition 49, 303-312

 

Fernandez M, Lopez-Jurado M, Aranda P and Urbano G 1996 Nutritional assessment of raw and processed faba bean (Vicia faba L.) cultivar Major in growing rats. Journal of Agricultural and Food Chemistry 44, 2766-2772

 

Friedman M 1996 Nutritional value of proteins from different food sources. A review. Journal of Agricultural and Food Chemistry 44, 6-29

 

Geervani P and Theophilus F 1980 Effect of home processing on the protein quality of selected legumes. Journal of Food Science 45, 707-710

 

Gupta M O, Lodha M L, Mehta S F, Rastogi D K and Singh J 1979 Effect of amino acid(s) and pulse supplement action on nutritional quality of normal and modified opaque-2-Maize. Journal of Agricultural and Food Chemistry 27, 787-790

 

Gupta V, Modgil R and Kalia M 2005 Effect of domestic processing on the in vivo protein quality of faba bean (Vicia faba). Journal of Food Science and Technology 42, 501-503

 

Janardhanan K, Vadivel V and Pugalenthi M 2003 Biodiversity in Indian under-exploited/tribal pulses. In: Improvement strategies for Leguminosae Biotechnology (editors: P K Jaiwal and R P Singh), pp. 353-405. Kluwer Academic Publishers, Britain.

 

Kirk J R 1984 Biological availability of nutrients in processed foods. Journal of Chemical Education 61, 364-368

 

Liener I E 1994 Implications of antinutritional components in soybean foods. CRC Critical Reviews in Food Science and Nutrition 34, 31-67

 

Makker H P S, Becker K, Abel H and Pawelzik E 1997 Nutrient contents, rumen protein digestibility and antinutritional factors in some colour and white flowering cultivars of Vicia faba beans. Journal of Science of Food and Agriculture 75, 511-520

 

Mohan V R and Janardhanan K 1995 Chemical determination of nutritional and antinutritional properties in the tribal pulses. Journal of Food Science and Technology 32, 465-469

 

Mulimani V H and Rudrappa G 1994 Effect of heat treatment and germination on alpha amylase inhibitor activity in chickpeas (Cicer arietinum L.). Plant Foods for Human Nutrition 46, 133-137

 

Mulimani V H and Vadiraj S 1993 Effect of heat treatment and germination on trypsin and chymotrypsin activities in sorghum (Sorghum bicolor (L.) Moench) seeds. Plant Foods for Human Nutrition 44, 221-226

 

Nestares T, Lopez-Frias M, Barrionuevo M and Urbano G 1996 Nutritional assessment of raw and processed chickpea (Cicer arietinum L.) protein in growing rats. Journal of Agricultural and Food Chemistry 44, 2760-2765

 

Nielson S S 1991 Digestibility of legume proteins. Food Technology 45, 112-118

 

Platt B S, Miller D S and Payre P R 1961 Protein values of human foods. In: Recent advances in Human Nutrition (editor: J F Brock), pp. 351-358. Little Brown and Co., Boston

 

Pugalenthi M, Siddhuraju P and Vadivel V 2006 Effect of soaking followed by cooking and the addition of a-galactosidase on oligosaccharides levels in different Canavalia accessions. Journal of Food Composition and Analysis 19, 512-517

 

Pugalenthi M, Vadivel V and Siddhuraju P 2005 Alternative food / feed perspectives of an under-utilized legume Mucuna pruriens var. utilis-a review. Plant Foods for Human Nutrition 60, 201-218

 

Rajaram N and Janardhanan K 1992 The chemical composition and nutritional potential of the tribal pulse, Abrus precatorius L. Plant Foods for Human Nutrition 42, 285-291

 

Sadasivam S and Manickam A 1992 Phenolics. In: Biochemical methods for agricultural sciences, pp. 187-188. Wiley Eastern Ltd, New Delhi, India

 

Sagarbieri U C 1989 Composition and nutritive value of beans (Phaseolus vulgaris L.) wld. Reviews in Nutrition and Dietetics 60, 132-186

 

Saharan K and Khetarpaul N 1994 Protein quality traits of vegetable and field peas: Varietal differences. Plant Foods for Human Nutrition 45, 11-22

 

Sanoja S and Bender E 1983 The effect of cooked legumes on mucosal cell turnover in the rat. Journal of Nutrition 43, 89-95

 

Seena S, Sridhar K R and Bhagya B 2005 Biochemical and biological evaluation of an unconventional legume, Canavalia maritima of coastal sand dunes of India. Tropical and Subtropical Agroecosystems 5, 1-14

 

Siddhuraju P and Becker K 2005 Nutritional and antinutritional composition, in vitro amino acid availability, starch digestibility and predicted glycemic index of differentially processed mucuna beans (Mucuna pruriens var. utilis): an under-utilized legume. Food Chemistry 91, 275-286

 

Siddhuraju P, Vijayakumari K and Janardhanan K 1992 Nutritional and chemical evaluation of raw seeds of the tribal pulse Vigna trilobata (L.) Verdc. International Journal of Food Science and Nutrition 43, 97-103

 

Vadivel V and Janardhanan K 1999 Chemical composition of some little known / wild legumes of South India. Journal of Swamy Botanical Club. 16, 55-60

 

Vadivel V and Pugalenthi M 2007 Biological value and protein quality of raw and processed seeds of Mucuna pruriens var. utilis. Livestock Research for Rural Development, volume 19, article # 97 http://www.cipav.org.co/lrrd/lrrd19/7/vadi 19097.htm

 

Vijayakumari K, Pugalenthi M and Vadivel V 2007 Effect of soaking and hydrothermal processing methods on the levels of antinutrients and in vitro protein digestibility of Bauhinia purpurea L. seeds. Food Chemistry 103, 968-975

 

Vijayakumari K, Siddhuraju P and Janardhanan K 1995 Effects of various water or hydrothermal treatments on certain antinutritional compounds in the seeds of the tribal pulse, Dolichos lablab var. vulgaris L. Plant Foods for Human Nutrition 48, 17-29

 

Vijayakumari K, Siddhuraju P and Janardhanan K 1996 Effect of soaking, cooking and autoclaving on the phytic acid and oligosaccharides content in the tribal pulse, Mucuna monosperma. Food Chemistry 55, 173-177

 

Vijayakumari K, Siddhuraju P and Janardhanan K 1997 Chemical composition, amino acid content and protein quality of the little-known legume Bauhinia purpurea L. Journal of Science of Food and Agriculture 73, 279-286

 

Vijayakumari K, Siddhuraju P, Pugalenthi M and Janardhanan K 1998 Effect of soaking and heat processing on the levels of antinutrients and digestible proteins in seeds of Vigna aconitifolia and Vigna sinenesis. Food Chemistry 63, 259-264

 

Wheeler E L and Ferrel R E 1971 A method for phytic acid determination in wheat and wheat fractions. Cereal Chemistry 48, 312-320



Received 18 September 2007; Accepted 21 September 2007; Published 1 November 2007

Go to top