STUDI ISOTERM SORPSI LEMBAB DAN FRAKSI AIR TERIKAT PADA TEPUNG GAPLEK

Purnomosari, Dyah (2008) STUDI ISOTERM SORPSI LEMBAB DAN FRAKSI AIR TERIKAT PADA TEPUNG GAPLEK. Other thesis, Universitas Sebelas Maret.

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    Abstract

    The simplest processing of cassava is sun drying, yielding a product locally know as gaplek, which may further be processed later into gaplek flour. As in Indonesia the economic value of cassava is considerably low, no serius attention is given on drying the flour. Good quality gaplek flour has moisture close to its primary bound water content to prevent microbial, chemical, or enzymatic degradation. Gaplek flour is hygrocopic, easily absorb moisture from the surroundings while in transport or during storage leading to increasing water content and water activity and eventually product damage. Knowledge of moisture sorption pattern of gaplek flour is of considerable importance. The pattern can be deduced from moisture sorption curve. Objectives of the study were to obtain gaplek flour adsorption pattern toward air moisture, bound water fraction (primary, secondary, and tertiary), proper drying process, and flour stability during transportation and storage based on moisture sorption isotherm curve. The curve was determined by conditioning gaplek flour at varying water activities (aw) using saturated salt solution at 28 0C. Data on water content at equilibrium were then plotted against water activity, and a polynomial of order three was estimated. Limit of primary bound water was determined using BET (Braunauer-Emmet-Teller) equitation. That of secondary one was determined by plotting log (1-aw) against water content at equilibrium, and that of tertiary one realized when aw = 1. It can be concluded that moisture sorption isotherm curve of gaplek flour at 28 0C resembled a sigmoid one (look like S) having estimated equation y = 220,92 x3 – 224,68 x2 + 77,267 x – 0,0188. Limits of primary, secondary, and tertiary bound water content were respectively 5,9242 % db (aw 0,1064), 5,9242 % db – 21,928 % db (aw 0,1064 – 0,7217), and 21,928 % db - 73.4882 % db (aw 0,7217 - 1). In gaplek flour production process, drying must be done until moisture content close its primary bound water content i.e. 5,9242 %db. With this figure, the products were stable during transportation and in storage. Keywords: moisture sorption isotherm, bound water fraction, gaplek flour.

    Item Type: Thesis (Other)
    Subjects: S Agriculture > SB Plant culture
    Divisions: Fakultas Pertanian
    Depositing User: Users 837 not found.
    Date Deposited: 18 Aug 2013 22:39
    Last Modified: 18 Aug 2013 22:39
    URI: https://eprints.uns.ac.id/id/eprint/9925

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