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Size Reduction

Size Reduction. Anugrah Wiyani. PENDAHULUAN. Definisi dan tujuan. Pengecilan ukuran bahan meliputi juga pemotongan , pemecahan dan penggilingan pada bahan makanan . Tujuan: Memperbesar luas permukaan bahan . Meningkatkan efisiensi proses pengadukan

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Size Reduction

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  1. Size Reduction • Anugrah Wiyani

  2. PENDAHULUAN

  3. Definisi dan tujuan • Pengecilanukuranbahanmeliputijugapemotongan, pemecahandanpenggilingan pada bahan makanan. Tujuan: • Memperbesarluaspermukaanbahan. • Meningkatkanefisiensiprosespengadukan • Memecahbahan yang mengandungmolekul/senyawa/bahanberhargauntukdipisahkan

  4. Pengecilanukurandalamindustripangan • penggilinganbiji, • pengupasanbuah-buahan, • penggilingantangkaibuah, • pengirisanikanmenjadifillet, • pengecilanzatpadatmenjadibagian-bagian yang lebihkeciluntukmempertinggidayakelezatandanmempertinggidayacampur.

  5. Teknik pengecilan ukuran • bahan padat : penghancuran dan pemotongan • bahan cair : emulsifikasi atau otomisasi.

  6. Kick’s law the energy required to reduce the size of particles is proportional to the ratio of the initial size of a typical dimension to the final size of that dimension E(J.kg-1) = the energy required per mass of feed (W/(kg/s)) KK = Kick’s constant, d1 (m) = the average initial size of pieces, d2 (m) = the average size of ground particles. d1/d2 = the size reduction ratio (RR) and is used to evaluate the relative performance of different types of equipment. Coarse grinding has RRs below 8:1, whereas in fine grinding, ratios can exceed 100:1

  7. Rittinger’s law the energy required for size reduction is proportional to the change in surface area of the pieces of food E(J.kg-1) = the energy required per mass of feed (W/(kg/s)) KR = Rittinger’s constant, d1 (m) = the average initial size of pieces, d2 (m) = the average size of ground particles.

  8. Bond’s law E(J.kg-1) = the energy required per mass of feed (W/(kg/s)) W (J kg-1) = the Bond Work Index (40,000–80,000 J kg-1 for hard foods Such as sugar or grain) d1 (m) = diameter of sieve aperture that allows 80% of the mass of the feed to pass d2 (m) = diameter of sieve aperture that allows 80% of the mass of the ground material to pass.

  9. Mesin pengayak • Mesin ayakan ini adalah pengayak manual. Dengan mesin penggetar di bawah dan susunan ayakan dengan ukuran yang berbeda. Dari atas adalah ukuran mesh yang terkecil hingga terbesar makin ke bawah. Hingga paling bawah adalah wadah penampung.

  10. Satuan Mesh • Mesh : jumlah lubang dalam 1 inchi persegi. • Contoh : ayakan 10 mesh, artinya sepanjang 1 inch terdapat 10 lubang dan kawatnya. Maka: • Jarak antar pusat kawat yang satu dengan kawat berikutnya = 1/10 =0,1 in.

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