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Analisis Sifat Fisik

Analisis Sifat Fisik. TEXTURE ANALYSIS. Nugraha Edhi Suyatma Department of Food Science and Technology Bogor Agricultural University - 2010. Importance of Texture.

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Analisis Sifat Fisik

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  1. AnalisisSifatFisik TEXTURE ANALYSIS Nugraha Edhi Suyatma Department of Food Science and Technology Bogor Agricultural University - 2010

  2. Importance of Texture The importance of texture in the overall acceptability of foods varies widely, depending upon the type of food. We could arbitrarily break it into three groups: Critical: Foods in which texture is the dominant quality characteristic; for example, meat, potato chips, cornflakes and celery. Important: Foods in which texture makes a significant but not a dominant contribution to the overall quality, contributing, more or less equally, with flavor and appearance; for example, most fruits, vegetables, cheeses, bread, most other cereal-based foods and candy fall into this category. Minor: Foods in which texture makes a negligible contribution to the overall quality; examples are most beverages and thin soups.

  3. Relations Between Textural Parameters and Popular Nomenclature

  4. Understanding Stress and Strain • Stress: the intensity of force components (pressure or mechanical action) acting on a body, expressed as force (F) per unit area (A) of food material (consider pressure or mechanical action as stress) • Strain: change in size or shape of a body in response to the applied stress, non-dimensional parameter. Reported as a ratio or percentage of the change to the original size or shape.

  5. Shear Type of stress • Compressive (directed toward the material) • Tensile(directed away from the material) • Shearing(directed tangentially to the material) Tensile Compression

  6. AnalisisTekstur

  7. Alat Pengukur tekstur dan kurvanya Instron Universal Testing Machine

  8. Texture Analyzer (Stable micro systems)

  9. Texture Analyzer (Stable micro systems) Needle: pengukuran firmness (buah, cake, keju, dll)

  10. Texture Analyzer (Stable micro systems) SPHERICAL: pengukuran freshness (cake, cheese)

  11. Texture Analyzer (Stable micro systems) CONICAL: pengukuran spreadability (butter, margarine)

  12. Texture Analyzer (Stable micro systems) CYLINDER: index of hardness, firmness or yieldpoint (gels, pectins, yoghurts, margarine)

  13. VIDEO Aplikasi Texture AnalyzerPengukuran bloom strength

  14. VIDEO Texture AnalyzerHardness and stickeness of chewy candy

  15. Texture Analyzer (Stable micro systems) Pengujian sealing tutup pot yoghurt

  16. VIDEO:Food Texture Analysis

  17. Texture Profile Analysis

  18. TPA - The History • General Foods texturometer developed • Force/time plot became known as a texture profile • Szczesniak defined specific terms which correlated well with sensory panel scores - texture profile analysis

  19. TPA - The History • simulasi pada saat proses pengunyahan • Dengan memberikan gaya tekan (compression) terhadap produk sebanyak dua kali. • Dapat diukur: • Kekerasan (hardness) • Elastisitas (elasticity) • Kerapuhan (fracturability atau brittleness) • Cohesiveness • Daya kunyah (chewiness) • Kelengketan (gumminess/stickiness)

  20. Texture Profile Analysis

  21. TPA (TEXTURE PROFILE ANALYSIS) • Known as the “two bite test” • Provides textural parameters which correlate well withsensory evaluation parameters

  22. TPA (TEXTURE PROFILE ANALYSIS) FIRST BITE • Known as the “two bite test” • Provides textural parameters which correlate well withsensory evaluation parameters FORCE TIME

  23. TPA (TEXTURE PROFILE ANALYSIS) SECOND BITE • Known as the “two bite test” • Provides textural parameters which correlate well withsensory evaluation parameters FORCE TIME

  24. TPA (TEXTURE PROFILE ANALYSIS) Movement of the Probe Force o Time

  25. TPA (TEXTURE PROFILE ANALYSIS) Movement of the PROBE Force o DOWN Time ‘COMPRESSION’

  26. TPA (TEXTURE PROFILE ANALYSIS) Movement of the PROBE Force o DOWN Time ‘COMPRESSION’

  27. TPA (TEXTURE PROFILE ANALYSIS) Movement of the PROBE UP Force o Time ‘Decompression’

  28. TPA (TEXTURE PROFILE ANALYSIS) Movement of the PROBE Force o Time DOWN

  29. TPA (TEXTURE PROFILE ANALYSIS) Movement of the PROBE UP Force o Time

  30. TPA (TEXTURE PROFILE ANALYSIS) Analysis of the data Fracturability Force o Time

  31. Definition seberapa kuat suatu produk menahan gaya tekan. Nilai ditentukan dari nilai F puncak yang pertama NB - Not always present TPA (TEXTURE PROFILE ANALYSIS) Analysis of the data Fracturability Force o Time

  32. TPA (TEXTURE PROFILE ANALYSIS) Analysis of the data Hardness 1 Hardness 2 Force o Time

  33. Definition daya tahan untuk pecah/patah akibat gaya tekan yang diberikan (hanya ada 1 peak). Dikenal juga sbg “firmness”. TPA (TEXTURE PROFILE ANALYSIS) Analysis of the data Hardness Hardness 2 Force o Time

  34. TPA (TEXTURE PROFILE ANALYSIS) Analysis of the data Area 1 Area 2 Force B A o Time

  35. Cohesiveness Dihitung dari luasan di bawah kurva pada tekanan kedua (A2) dibagi dengan luasan di bawah kurva pada tekanan pertama (A1) TPA (TEXTURE PROFILE ANALYSIS) Analysis of the data Force B A o Time

  36. TPA (TEXTURE PROFILE ANALYSIS) Analysis of the data Force B A o Time

  37. TPA (TEXTURE PROFILE ANALYSIS) Analysis of the data Force B A o Time

  38. TPA (TEXTURE PROFILE ANALYSIS) Analysis of the data Springiness Force o Time

  39. Definition The height that the food recovers during the time that elapses between the end of the first cycle and the start of the second cycle. TPA (TEXTURE PROFILE ANALYSIS) Analysis of the data Springiness Force o Time

  40. TPA (TEXTURE PROFILE ANALYSIS) Analysis of the data Springiness Force o Time

  41. TPA (TEXTURE PROFILE ANALYSIS) Analysis of the data Work of Adhesion Force o Time Adhesivness

  42. Definition The negative area for the first compression cycle - representing the work needed to overcome the attractive forces between the surfaces of the probe and the food. TPA (TEXTURE PROFILE ANALYSIS) Analysis of the data Work of Adhesion Force o Time

  43. Definition The maximum negative force of the first compression cycle TPA (TEXTURE PROFILE ANALYSIS) Analysis of the data Force o Time Adhesivness

  44. Texture Profile Analysis (TPA)

  45. CONTOH KASUS Kentangdiirisbentukkubusdgnberukuran 1 cm3dankemudiandirebussecaraterpisah: A – 0 menit (mentah) B – 1 menit C – 2 menit D – 3 menit Segerasetelahdiberiperlakuan, kentangtersebutdiukurdgn TA instruments dengan spindle “heavy duty platform dgnukuran 35 mm silinder”

  46. CONTOH KASUS Jika diperoleh profil tekstur sbb, parameter apakah yang dapat digunakan sebagai perbandingan? Dapatkah diketahui nilai brittleness??

  47. CONTOH KASUS Apakah kesimpulan yang dapat diperoleh dari data diatas??

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