Chemical Constituents (Proximate, Minerals, Bioactive Compounds) of Pea [Pisum sativum (L.)] Shells

Amita Beniwal1,*, Vikram1, Savita Singh1, Veenu Sangwan1, Darshan Punia1
1Department of Foods and Nutrition, CCS Haryana Agricultural University, Hisar-125 004, Haryana, India.
Background: Peas are preserved by freezing in pea processing industries because of seasonal limitations; there is a vast amount of pea peels as solid waste generated. Now days, the nutritional and techno-functional properties of by-products play an important role in the development of functional and enriched products in the food sector. The current study aim to analyze the nutrients content in pea shells. The result suggests pea shells can be used for value-addition in products and presence of antioxidant in pea shell powder indicates a better health effect if consumed.  

Methods: In this laboratory investigation during 2017-2018 peas were collected from market a single lot and analyzed for chemical constituents. In this connection, a fibrous coat of pea shells was separated, dried and prepared powder to perform nutritional analysis. 

Result: The study result indicates that pea shells have high nutritive value, e.g. protein (17.76%), total dietary fiber (21.04%), calcium (803.33 mg/100 g), iron (10.70 mg/100 g), potassium (1078.75 mg/100 g), magnesium (1029.55 mg/100 g) and bioactive compounds. Fresh pea shells have higher antioxidant activity (91%) compared to powder (86%). The total phenols, vitamin C and â-carotene strongly correlated with antioxidant activity. During the storage study, total phenols and antioxidant activity significantly decreased while on 90 days it was increased.
The production of peas at the world level, India is the second producer (4 million tons/annum) after china, which contributed 22.9% (FAOSTAT 2019). In India pea (Pisum sativum) is growing as a vegetable in different states due to suitable climate zone (winter) and fulfilling the aim of human and animal feed consumption Mmihailvoic et al. (2005). The peel of seed is not pea peel waste; the outer covering is considered as a waste. India’s yearly generated more than 1 million tons of pea peel is discarded as waste or use an animal feed (Upasana and Vinay, 2018). Due to the seasonal and perishable nature of peas, their accessibility is short, which generates the demand for its preservation (Garg et al., 2014). Now a days, the nutritional and techno-functional properties of by-products (fruits and vegetables) play an important role in the development of functional and enriched products in the food sector because they are promising sources of functional and bioactive compounds (Sagar et al., 2018) and due to antioxidant and anti-germicide properties, traditionally used as a remedy to prevent various degenerative diseases. An alternative path for consumption of plants components (fiber-rich) are the value addition of food, dietary supplementation and fortification will not boost the nutritional status but provide health benefits to peoples (Kiran, 2017). Plant proteins, primarily originating from industrial by-products, have gained attention in recent researches and also more demand for pulses and cereals having phenols content. Drying is an essential method to preserve of agricultural products, reducing their bulk and ensuring better shelf life. Pea pods have a good amount of moisture, so its storage is difficult (Garg, 2015). Pea shells can be dehydrated without much quality deterioration and can be utilized a nutrient rich mix for product development. Based on experiment we propose that pea by-products hold many biologically active compounds which attain value addition or supplementation of products for nutraceutical use. The present investigation aims to prepare pea shells powder, analyzed nutritional properties and develop value-added products. 
This study was performed in 2018 in February at the Food and nutrition department, College of Home Science, CCS HAU, Hisar, Haryana.
Procurement of material
Fresh peas were obtained from the vegetable market, Hisar, Haryana, India in single lots.
Preparation of samples (Fig 1)
Fresh pea pods shelled and drenched under tap water to remove dirt and impurities. After that, pods were dipped in hot water (60°C for 10 minutes) and outspread over filter paper sheets to drain excess water. Separated the layer manually, chopped finely (edible layer) and firstly dehydrated in shadow (12 hours) at ambient temperature, after that, oven drying (24 hours, 45°C). The dried shells were ground to make a fine powder (sieve size 420 microns) and stored (22±2°C) in air-tight plastic bags for the next step.

Fig 1: Procedure of preparation of pea shells powder.

Nutritional evaluation of pea shells
Fresh pea shells and powder were analyzed for the nutrients content (samples were performed in triplicates). 
Proximate composition (moisture, crude protein, crude fat, ash, crude fiber) examined by the standard methods (AOAC 2000) and total carbohydrate and energy calculated by difference and multiplication method. Protein fractions examined by Naik (1968) modified version of Osborne (1907) method, dietary fiber (Total, insoluble and soluble) determined by Furda (1981) and total Minerals investigated by Lindsey and Norwell (1969), method by atomic absorption spectro photometer 2380, (PERKIN-ELMER, USA) digested (acid) samples. Bioactive compounds (Total phenolic content by Zhishen et al. (1999), Total Flavonoids by Singleton and Rossi (1965), Antioxidant activity by  (Brand-william et al. 1995), Vitamin C and β-carotene performed by AOAC (2000) method.  
Storage study
Pea shells powder were stored at room temperature (22±3°C) for 90 days and analyzed moisture, total phenols, flavonoids and antioxidant activity.
Statistical analysis
Data analyzed by using standard statistical methods ANOVA (CRD) and interpretation presented through average and standard error. The significant (p<0.05) proved by C.D. value (Sheoran and Pannu 1999).
Nutritional parameters of pea shells
The pea shells finding of proximate composition conferred in Table 1. Almost similar results regarding moisture content (88.47%) in pea shells were reported by Krimat et al., 2021 (87.79%) and Upasana et al., (2018) reported lower moisture (83.41%) content. A higher and lesser amount of moisture in pea shells powder reported by Hanan et al., (2020) (10%) in green pea pods.  Protein content in present study reported 17.76 gm/100 gm, whereas a higher protein (19.79, 18.29 gm/100 gm) content in pea shells powder was recorded by Upasana et al., (2018), Rathore et al., (2021) in chickpea and lower amount of protein content was noticed by Garg (2015) (14.8%) and Hanan et al., (2020) (11.99%) compared to present study. Almost similar results in appreciate to fats (0.43%) content were by Garg et al., (2015). A higher fat content (1.34%) noticed in green pea peels by Fendri et al., 2016 (0.87%) and 3.88% Hanan et al., 2020.  Similar results of ash (5.04%) content reported by Garg (2015) (5.0%) and Upasana et al., 2018 (5.65%) in pea peel. A higher value noticed by  Aparicio et al., 2010 (6.6 gm/100 gm) and another study addressed by Hanan et al., (2020) reported lower amount of ash content 4.61% compared to present study. Crude fiber content (7.76%) in pea shells powder are close proximity (7.86%) reported by Garg (2015). The lower values for carbohydrates reported by Garg (2015) (61.43%) than present investigation (65.11%) and a higher value reported by Hanan et al., 2020 (69.5%). Garg (2015) reported 309.11 kcal/100 gm energy content, whereas 335.43 kcal/100 gm found in pea pod powder present study. On the contrary, Bakshi  and  Wadhwa (2013) reported a higher concentration of albumin (59.3%) followed by glutelin (17.8%), globulin (15.6%) and prolamin (7.3%) when compared to present results. Lu et al., 2020 reported 3-5% (prolamin and glutelin) protein fractions. The dietary fibers with the amount, 21.04%, 17.03% and 4.01% total, insoluble and soluble content, respectively found in present study. Aparicio et al., (2010) reported contradicting results with a high amount of dietary fiber content 58.6%, 54.4% and 4.2% respectively. Hanan et al., (2020) found that insoluble and soluble content in pea pods powder was 25.04% and 11.08%. Rudra et al., (2020) reported that the lesser amount of fiber content in plant sample due to exclusion of the parchment layer with the intention to gain non-disruptive fibrous materials. In the present study, calcium content was found 803.33 mg/100 gm in pea shells powder. Almost similar results reported 0.83 gm/100 gm calcium in pea pods powder by Garg (2015) but a lower amount of calcium (0.77 gm/100 gm) and iron (1.20 mg/100 g) content in pea pods was revealed by Aparicio et al., (2010) and Bakshi and Wadhwa, 2013 (0.39%). Inside the present investigation, potassium content discovered 1078.75 mg/100 gm in pea shells powder comparable to 1.03 gm/100 gm potassium content of pea pods reported by Aparicio et al., (2010) and Bakshi and Wadhwa 2013 (0.80%). Pea shells powder had 1029.55, 47.37, 10.70, 3.28 and 0.59 mg/100 gm magnesium, sodium, iron, zinc and manganese content respectively.  Aparicio et al., (2010) reported a contradictory results of minerals i.e. magnesium (0.21 gm/100 g), sodium (0.14 gm/100 g), iron, zinc and manganese as 1.20, 0.27 and 0.06 mg/100 g, respectively. Bakshi and Wadhwa (2013)  reported that the peas by-products containing minerals  like magnesium (0.22%), sodium, Iron, zinc and manganese  content were 189.0, 9.0, 27.58 and 18.4 (ppm) per 100 gm,  respectively. Hanan et al., 2020 reported a lower amount (2.66 mg/100 gm) of iron in pea pods powder.

Table 1: Nutrients composition of pea shells.

Bioactive compounds in pea shells
From the existing investigation (Table 2) it was found that the quantity of total phenols in fresh and pea shells powder was 36.46 and 304.62 mg GAE/100 g, respectively  which was higher compared to the values (62.5 mg/100 gm) noted by by Hadrich et al., (2014) in dry pea pods. The concentration of phenols depends upon the kind of seeds variety. The flavonoids content was found to be 7.3 and 24.44 mg RE/100 gm in fresh and pea shells powder in existing experiments.  Flavonoids amount in ethyle acetyate and methanol extraction were 22 and 3.5 mg QE/100 gm as reported by Hadrich et al., (2014). The antioxidant activity (FRAP) observed in present study was 133.33 and 1000.00 mgTE/100 gm in fresh pea shells and powder, respectively. The antioxidant activity (DPPH) was 2,595.69 and 2468.0 mg TE/100 gm in fresh pea shells and powder in present study. Hadrich et al., (2014) reported 650 µg/ml (methanol) and 350 µg/ml (ethyl acetate) in extract of pea pods. The percent of inhibition (DPPH) was 91.05% in present study whereas; Ishaq et al., (2015) reported 75% antioxidant activity and Jalilisafaryan et al., (2016) found 91.03% antioxidant activity  through DPPH in peas. On the contradicted results reported by Krimat et al., 2021 total phenolic content in fresh and powder in peas were 4.34 and 4.05 to 13.29 mgGAE/gDW and flavonoids content 2.91 and 2.74 to 5.76 mgQE/gDW respectively. The formation of Maillard reaction products may add antioxidant activity and interfere with the Folin-Ciocalteu, DPPH and FRAP test (Sousa et al., 2018). Hanan et al., 2020 reported carotenoids content 7.628 mg/100 gm but in present investigation fresh pea shells and powder reported 1.2 and 56.87 µg/100 gm. In the present investigation, vitamin C was found higher in fresh pea shells (35.9 mg/100 g) compared to pea shell powder (6.6 mg/100 g). Similarly, Srivastava and Jain 2019 reported that the ascorbic acid content was decreased in dried ker compared to fresh form. β-carotene in fresh pea shell and powder was recorded 387 and 2483.87 µg/100 gm. El-din et al. (2013) reported that different fresh vegetables contain β-carotene (41.40 to 340.51 µg/100 gm) and vitamin C (33.83 to 92.65 mg/100 gm) in different range. 

Table 2: Bioactive compounds in pea shells.

Storage study of bioactive constituents in pea shells powder
The storage study results of bioactive compounds depicted in Table 3 indicated a significant decrease (p<0.05) in total phenols in pea shells powder after 15 days to 60 days but significantly increased at 90 days. Similar results reported by Sonawane and Arya (2015) in wood apple and jambhul and Syamaladevi et al., (2012) in canned black and blue berries, the total phenols were significantly increased during storage. This change during storage due to chemical reaction or may be external factors (air, light and temperature) or moisture and cell destruction affected the stability of polyphenols. In the present investigation, the total flavonoids amount in pea shells powder was decreased significantly throughout storage periods. Sonawane and Arya 2015 noticed a simliar decreasing pattern of flavonoids content in wood apple and jambhul. Antioxidant capacity measured by FRAP found reduction during the storage period from 1001 to 959.28 mgTE/100 gm but at 90 days increasing pattern was noticed. The degradation of the amount of flavonids and total phenols in pea shells powder reduced the antioxidant capacity measured by FRAP. The antioxidant capacity measured by DPPH method shows a significant reduction but at 90 days it was significantly increased 2,199.62 mgTE/100 gm. Similarly result pattern was reported by Sonawane and Arya (2015) in wood apple and jambhul. The moisture content was consistently increased in pea shells powder during the storage ranging from 3.89 to 5.02%. Breda et al., (2012) reported a similar result during storage in guavira pulp powder. Moisture content influences shelf life during storage, excessive water supports the microbial growth increased leading to decreased shelf life. Total phenols, vitamin C and β-carotene strongly correlated with DPPH while poorly (weak) correlated with flavonoids (Table 4). β-carotene (0.95) and flavonoids (0.66) strongly correlated with FRAP while very poor correlated with total phenols (-0.33) and vitamin C (0.35) was noticed. No significant correlation was observed in this experiment.

Table 3: Bioactive compounds in pea shells powder (0 to 90 days) during storage study.

Table 4: Correlation of bioactive compounds in pea shell powder.

This study reveals peas shell is a superb source of nutrients similar to pea grains. This study highlights the scope that incorporation of pea shells for value addition in traditional recipes can be encouraging and popularizing in terms of boost up the level of nutrients (minerals, antioxidants, dietary fiber and protein). Present effects advocate that pea shells hold many biologically energetic materials that can be applied to reap the high cost and prepared value-added products for nutraceutical uses. The value-added products are developed by incorporating powder (pea shells) at the market or household levels, which solve the environmental problem and are an appropriate choice for fulfillments the nutritional demand of the country. Due to its high nutritional properties, this could be a significant role in alleviating the protein- energy malnutrition of developing countries. Its antioxidants activity shows that it can be used for therapeutic purposes in many diseases.

  1. AOAC. (2000). Official Methods of Analysis (17 Edn.), Association of Official Analytical Chemist International. AOAC International, Gaithersburg, MD, USA.

  2. Aparicio, I.M., Cuenca, A.R., Suarez, M.J.V., Revilla, M.A.Z. and Sanz, M.D.T. (2010). Pea pod, broad bean pod and okara, potential sources of functional compounds. Food Science Technology. 43: 1467-1470.

  3. Bakshi, M.P.S. and Wadhwa, M. (2013). Nutritional evaluation of cannery and fruit wastes as livestock feed. Indian Journal of Animal Science. 83: 1198-1202.

  4. Brand-williams, Cuvelier, M.E. and Berset, C.L.W.T. (1995). Use of a free radical method to evaluate antioxidant activity. LWT-Food Science Technology. 28: 25-30.

  5. Breda, A.C., Argandona, E.J.S. and Correia, A.C.C. (2012). Shelf life of powdered Campomanesia adamantium pulp in controlled environments. Food Chemistry. 135: 2960- 2964.

  6. El-Din, M.H.A.S., Kader, M.M.A., Makhlouf, S.K. and Mohamed, O.S.S. (2013). Effect of some cooking methods on natural antioxidants and their activities in some Brassica vegetables.  World Applied Sciences Journal. 26: 697-703. 

  7. FAOSTAT. (2019).

  8. Fendri, L.B., Chaari, F., Kallel, F., Ellouzi, S.Z. Ghorbel, R. et al. (2016). Pea and broad bean pods as a natural source of dietary fiber: The impact on texture and sensory properties  of cake. Journal of Food Science. 81(10): 2360-2366. 

  9. Furda, I. (1981). Simultaneous Analysis of Soluble and Insoluble Dietary Fiber. In: The Analysis of Fiber in Foods [James, W.P.T. and Theander, O. (Eds)]. Marcel Dekker, New York, NY).

  10. Garg, M. (2015). Nutritional evaluation and utilization of pea pod powder for preparation of jaggery biscuits. Journal Food Process Technology. 6: 552. doi: 10.4172/2157-7110. 1000522.

  11. Garg. M., Sharma, S., Varmani, G.S. and Sadhu, D.S. (2014). Drying kinetics of thin layer pea pods using tray drying.  International  Journal of Food Nutrition. 3: 61-66.

  12. Hadrich, F., Mahdi, E.A., Boukhris, M., Sayadi, S. and Cherif, S. (2014). Valorization of the peel of pea: Pisum sativum by evaluation of its antioxidant and antimicrobial activities. Journal of Oleo Science. 63: 1177-1183. 

  13. Hanan, E., Rudra, S.G., Sagar, V.R. and Sharma, V. (2020).  Utilization  of pea pod powder for formulation of instant pea soup powder. Journal Food Processing and Preservation. 

  14. Ishaq, A. and William, K. (2015). DNA protective activity of peels of some vegetables wastes. Journal of Bioresource Manage. 2: 1-6. 

  15. Jalilisafaryan, M., Ganjloo, A., Bimakr, M. and Zarringhalami, S. (2016). Optimization of ultrasound-assisted extraction, preliminary characterization and in vitro antioxidant activity of polysaccharides from green pea pods.  Foods. 5: 78. doi: 10.3390/foods5040078.

  16. Kiran, B. and Neetu, S. (2017). Utilization of vegetable waste as a source of dietary fiber rich muffins and biscuits for old age. International Journal of Food Science and Nutrition. 2: 31-34. 

  17. Krimat, H.L., Dahmoune, F., Hentabli, M., Spigno, G. and Madani, K. (2021). Physicochemical, functional and bioactive proper ties of pea [Pisum sativum (L.)] pods microwave and convective dried powders.

  18. Lindsay, W.L. and Norvell, W.A. (1969). Equilibrium relationship of Zn, Fe, Ca and H with EDTA and DTPA in soils. Soil Science Society Am. Proc. 33: 62-68.

  19. Lu, Z.X., He, J.F., Zhang, Y.C. and Bing, D.J. (2020). Composition, physicochemical properties of pea protein and its application  in functional foods. Critical Reviews in Food Science and Nutrition. 60: 2593-2605.

  20. Mmihailovic, V., Mikic, A., Eric, P., Vasiljevic, S., Cupina, B. et al. (2005). Protein pea in animal feeding. Biotechnology in Animal Husbandry. 21: 281-285.

  21. Naik, M.S. (1968). Lysine and tryptophan in protein fractions of sorghum. Indian Journal of Genetic Plant Breeding. 28: 142-146.

  22. Osborne, T.B. (1907). The Proteins of the Wheat Kernel. Camegie Inst. Wash., Publ. No. 84. 

  23. Rathore, M., Prakash, H.G. and Bala, S. (2021). Evaluation of the nutritional quality and health benefits of chickpea [Cicer arietinum (L.)] by using new technology in agriculture (Near Infra-red spectroscopy-2500). Asian Journal of Dairy and Food Research. 40: 123-126. 

  24. Rudra, S.G., Hanan, E., Sagar, V.R., Rakesh, R., Santanu, B. et al. (2020). Manufacturing of mayonnaise with pea pod powder as a functional ingredient. Journal of Food Measurement and Characterization. 14: 2402-2413. 

  25. Sagar, A.N., Pareek, S., Sharma, S., Yahia, M.E. and Lobo, G.M. (2018). Fruit and vegetable waste: Bioactive compounds, their extraction and possible utilization. Food Science and Food Safety. doi: 0.1111/1541-4337.12330.

  26. Sheoran, O.P. and Pannu, R.S. (1999). Statistical Package for Agricultural Workers. O.P. Stat College of Agriculture, Kaul, CCS Haryana Agricultural University, Hisar. India.

  27. Singleton, V.L. and Rossi, J.A. (1965). Calorimerty of total phenols with phosphomolybdic phasphotungttic acid reagents.  American Journal of Enology Viliculture. 16: 144-158.

  28. Sonawane, S.K. and Arya, S.S. (2015). Effect of drying and storage on bioactive components of jambhul and wood apple. Journal of Food Science and Technology. 52: 2833-2841. 

  29. Sousa, A.D. et al. (2018). Drying kinetics and effect of air-drying temperature on chemical composition of phyllanthus amarus and phyllanthus niruri.  Drying Technology. 36: 609-616.

  30. Srivastava, S. and Jain, D. (2019). Performance of solar drying and evaluation of phytochemical profile in an underutilized  fruit (Capparis decidua) ker. Asian Journal of Dairy and Food Research. 38: 224-230.

  31. Syamaladevi, R.M. andrews, P.K., Davies, N.M., Walters, T. and Sablani, S.S. (2012). Storage effects on anthocyanins, phenolics and antioxidant activity of thermally processed conventional and organic blueberries. Journal of the Science of Food and Agriculture. 92: 916-924.

  32. Upasana and Vinay, D. (2018). Nutritional evaluation of pea peel and pea peel extracted byproducts. International Journal of Food Science and Nutrition. 3: 65-67. 

  33. Zinshen, J., Mengcheng, T. and Jianming, W. (1999). The determination  of flavanoid contents in mulberry and their scavenging effects on superoxide radicals. Food Chemistry. 64: 555- 559. 

Editorial Board

View all (0)