Effects of Moisture Content and Impact Energy on the Cracking Characteristics of Walnuts
-
Feizollah Shahbazi
Abstract
A study was conducted to determine the effects of moisture content and energy of impact on the cracking characteristics of walnuts. A sample of fresh harvested walnuts was divided into four portions and conditioned under sunshine for different time durations to obtain different levels of moisture content [9.2–29.7%, wet basis (w.b.)]. An impact test apparatus was used to apply different impact energies in the range of 0.13–1.11 J to samples with different moisture content. Data obtained on the quantity of fully cracked and unbroken kernel, fully cracked but broken kernel and uncracked nuts were used in the computation of the nuts cracking characteristics. Results showed that moisture content, impact energy and interaction effects of these two variables have significant effect on the walnuts cracking characteristics. Full cracking of nuts increased with impact energy and decreasing moisture content. The optimum moisture content for cracking walnuts that gave the best result combination of high whole kernel yield and low kernel breakage was found to be about 16%. The optimum impact energy for cracking was found to be about 1.01 J (1.01 ± 0.1 J). The results of this study show that development of a centrifugal impact cracker, which uses impact to crack walnuts, is possible. In the designing of the walnut cracker, the radius and speed of the cracker should be such that create impact energy and velocity of about 1.01 J and 11 m/s, respectively, and walnuts should be conditioned to the moisture content of about 16% for optimum efficiency.
Notations
- Dg
Geometric mean diameter (mm)
- Ea
Absorbed impact energy (J)
- Ei
Impact energy (J)
- g
Acceleration due to gravity (m/s2)
- H
Drop height from base plate (m)
- H1
Original drop height (m)
- H2
Rebound height (m)
- L
Length (mm)
- M
Mass of the drop bar (kg)
- MC
Moisture content (% w.b.)
- NT
Total number of nuts
- N1
Number of fully cracked nuts with unbroken kernels
- N2
Number of fully cracked nuts with broken kernels
- N3
Number of uncracked nuts
- PCBK
Fully cracked nuts with broken kernels (%)
- PCUK
Fully cracked nuts with unbroken kernels (%)
- PUC
Uncracked nuts (%)
- T
Thickness, mm
- V
Impacting velocity (m/s)
- W
Width (mm)
References
1. EbrahimiA, ZareiA, FatahiR, Ghasemi VarnamkhastiM. Study on some morphological and physical attributes of walnut used in mass models. Sci Horticulturae2009;121:490–4.10.1016/j.scienta.2009.02.021Search in Google Scholar
2. GhafariA, CheginiGR, KhazaeiJ, VahdatiK. Design, construction and performance evaluation of the walnut cracking machine. Int J Nuts Related Sci2011;2:11–16.Search in Google Scholar
3. SharifianF, DerafshiHM. Mechanical behavior of walnut under cracking conditions. J Appl Sci2008;8:886–90.10.3923/jas.2008.886.890Search in Google Scholar
4. FigielA, KitaA. Drying kinetic, water activity, shrinkage and texture of walnut kernels. Acta Agrophysica2008;11:71–80.Search in Google Scholar
5. LaverdrineF, RavelA, VilletA, DucrosV, AlaryJ. Mineral composition of two walnut cultivars originating in France and California. Food Chem2000;68:347–51.10.1016/S0308-8146(99)00204-6Search in Google Scholar
6. NashSD, WestpfalM. Cardiovascular benefits of nuts. Am J Cardiol2005;95:963–5.10.1016/j.amjcard.2004.12.035Search in Google Scholar
7. PatelG. Essential fats in walnuts are good for the heart and diabetes. J Am Diet Assoc2005;105:1096–7.10.1016/j.jada.2005.05.193Search in Google Scholar
8. CortesB, NunezI, CofanM, GilabertR, Perez-HerazA, CasalsE, et al. Acute effects of high-fat meals enriched with walnuts or olive oil on postprandial endothelial function. J Am Coll Cardiol2006;48:1666–71.10.1016/j.jacc.2006.06.057Search in Google Scholar
9. BorgheiAM, TavakoliT, KhazaeiJ. Design, construction, and testing of walnut cracker. In: Proceedings of European Agricultural Engineering Conference, Warwick University, England, 2000.Search in Google Scholar
10. EbubekirA, YakupO. Physical and mechanical properties of some walnut (Juglans regia L.) cultivars. Int J Food Eng2008;4:Article 10.10.2202/1556-3758.1349Search in Google Scholar
11. AviaraNA, GwandzangMI, HaqueMA. Physical properties of guna seeds. J Agric Eng Res1999;73:105–11.10.1006/jaer.1998.0374Search in Google Scholar
12. OluwoleFA, AviaraNA, HaqueMA. Effect of moisture content and impact energy on the crackability of sheanut. Agric Eng Int: the CIGR Ejournal2007;8:07-002.Search in Google Scholar
13. OluwoleFA, AbdulrahimAT, OlalereRK. Effect of moisture content on the crackability of bambara groundnut using a centrifugal cracker. Int. Agrophysics2007;21:179–84.Search in Google Scholar
14. MakanjuolaGA. An evaluation of some centrifugal impaction devices for shelling melon seeds. J Agric Eng Res1975;20:71–7.10.1016/0021-8634(75)90097-9Search in Google Scholar
15. OdigbohEU. Impact egusi shelling machine. Trans ASAE1979;22:1264–9.10.13031/2013.35196Search in Google Scholar
16. AdigunYJ, OjeK. Thevetia fruit processing: energy requirements for cracking the nut. Proc Niger Soc Agric Eng (NSAE)1993;15:128–39.Search in Google Scholar
17. AsoegwuSN. Some physical properties and cracking energy of conophor nuts at different moisture content. Int Agrophysics1995;9:131–42.Search in Google Scholar
18. AkaniAO, OhanweCN, OmoniyiIO. Determination of optimum impact for decortication of bambara groundnut. Proc Niger Inst Agric Eng2000;22:87–9.Search in Google Scholar
19. KoyuncuMA, EkinciK, SavranE. Cracking characteristics of walnut. Biosys Eng2004;87:305–11.10.1016/j.biosystemseng.2003.11.001Search in Google Scholar
20. AltuntasE, ErkolM. The effects of moisture content, compression speeds and axes on mechanical properties of walnut cultivars. Food Bioprocess Technol2009;4:1288–95.10.1007/s11947-009-0283-ySearch in Google Scholar
21. RjabipourA, ShahbaziF, MohtasebiS, TabatabaeefarA. Airflow resistance in walnuts. J Agric Sci Technol2001;3:257–64.Search in Google Scholar
22. FluckRC, AhmedEM. Impact testing of fruits and vegetables. Trans ASAE1973;16:660–6.10.13031/2013.37597Search in Google Scholar
23. KimTH, OparaLU, HamptonJG, HardacreAK, MacKayBR. The effects of grain temperature on breakage susceptibility in maize. Biosys Eng2002;82:415–21.Search in Google Scholar
24. SAS. SAS User’s Guide: Statistics, Version 5 Edition. Statistical analysis system, Inc., Cary, NC., USA, 1985.Search in Google Scholar
25. KhazaeiJ, RasekhM, BorgheiAM. Physical and mechanical properties of almond and its kernel related to cracking and peeling. ASAE Paper No. 026153. St. Joseph, MI: ASAE, 2002.Search in Google Scholar
26. OluwoleFA, AviaraNA, HaqueMA. Development and performance tests of a sheanut cracker. J Food Eng2004;65:117–23.10.1016/j.jfoodeng.2004.01.004Search in Google Scholar
©2014 by Walter de Gruyter Berlin / Boston
Articles in the same Issue
- Frontmatter
- Mass Transfer Coefficients and Correlation of Supercritical Carbon Dioxide Extraction of Sarawak Black Pepper
- Higher Order Predictive Functional Control Versus Dynamical Matrix Control for a Milk Pasteurisation Process: Transfer Function Versus Finite Step Response Internal Models
- Fluidized Bed Drying of Sprouted Wheat(Triticum aestivum)
- Investigation of Hydrodynamics, Kinetics, Energetic and Exergetic Aspects of Fluidized Bed Drying of Rough Rice
- Flux Behavior and Quality of Effluent from a Poultry Processing Plant Treated by Membrane Bioreactor
- Experimental Analysis and Numerical Modeling of Microwave Reheating of Cylindrically Shaped Instant Rice
- Microwave, Air and Combined Microwave-Air Drying of Grape Leaves (Vitis vinifera L.) and the Determination of Some Quality Parameters
- Modelling the Influence of Time and Temperature on Respiration Rate of Fresh Fig and Diced Papaya
- Identification of Peanut Pods with Three or More Kernels by Machine Vision and Neural Network
- Effect of Drying Pre-treatments on the Yield and Bioactive Content of Oil Extracted from Gac Aril
- Effect of Pulsed Electric Field on Microstructure of Some Amino Acid Group of Soy Protein Isolates
- A Novel Modified Starch/Carboxymethyl Cellulose/Montmorillonite Bionanocomposite Film: Structural and Physical Properties
- Effects of Spray Drying Conditions on the Stability and Antioxidant Properties of Spray-Dried Soluble Maté
- Effect of Frying Time and Temperature on the Functional Properties of Carrot Pomace, Pulse Powder and Rice Flour–Based Extrudates
- Effects of Moisture Content and Impact Energy on the Cracking Characteristics of Walnuts
- Spray Drying of Karkade (Hibiscus sabdariffa L.) Calyces and Evaluation of the Product
- Optimization of Closed-Cycle Fluidized Bed Drying of Sesame Seeds Using Response Surface Methodology and Genetic Algorithms
- Assessment of Heat Transfer and Mass Change During Fruits and Vegetables Impingement Pre-Cooling
- High Temperature Short Time Air Puffed Ready-To-Eat (RTE) Tapioca–Peanut Snack: Process Parameters Optimization
Articles in the same Issue
- Frontmatter
- Mass Transfer Coefficients and Correlation of Supercritical Carbon Dioxide Extraction of Sarawak Black Pepper
- Higher Order Predictive Functional Control Versus Dynamical Matrix Control for a Milk Pasteurisation Process: Transfer Function Versus Finite Step Response Internal Models
- Fluidized Bed Drying of Sprouted Wheat(Triticum aestivum)
- Investigation of Hydrodynamics, Kinetics, Energetic and Exergetic Aspects of Fluidized Bed Drying of Rough Rice
- Flux Behavior and Quality of Effluent from a Poultry Processing Plant Treated by Membrane Bioreactor
- Experimental Analysis and Numerical Modeling of Microwave Reheating of Cylindrically Shaped Instant Rice
- Microwave, Air and Combined Microwave-Air Drying of Grape Leaves (Vitis vinifera L.) and the Determination of Some Quality Parameters
- Modelling the Influence of Time and Temperature on Respiration Rate of Fresh Fig and Diced Papaya
- Identification of Peanut Pods with Three or More Kernels by Machine Vision and Neural Network
- Effect of Drying Pre-treatments on the Yield and Bioactive Content of Oil Extracted from Gac Aril
- Effect of Pulsed Electric Field on Microstructure of Some Amino Acid Group of Soy Protein Isolates
- A Novel Modified Starch/Carboxymethyl Cellulose/Montmorillonite Bionanocomposite Film: Structural and Physical Properties
- Effects of Spray Drying Conditions on the Stability and Antioxidant Properties of Spray-Dried Soluble Maté
- Effect of Frying Time and Temperature on the Functional Properties of Carrot Pomace, Pulse Powder and Rice Flour–Based Extrudates
- Effects of Moisture Content and Impact Energy on the Cracking Characteristics of Walnuts
- Spray Drying of Karkade (Hibiscus sabdariffa L.) Calyces and Evaluation of the Product
- Optimization of Closed-Cycle Fluidized Bed Drying of Sesame Seeds Using Response Surface Methodology and Genetic Algorithms
- Assessment of Heat Transfer and Mass Change During Fruits and Vegetables Impingement Pre-Cooling
- High Temperature Short Time Air Puffed Ready-To-Eat (RTE) Tapioca–Peanut Snack: Process Parameters Optimization
