Glass transition and sorption properties of Köftür: a dehydrated fruit-based product

AKTAŞ, Nesimi; GERÇEKASLAN, Kamil Emre

doi:10.1590/fst.34419

Nesimi AKTAŞ ^**Corresponding author: naktas@nevsehir.edu.tr

Food Engineering Department, Engineering and Architecture Faculty, Nevşehir Hacı Bektaş Veli University, Nevşehir, Turkey

https://orcid.org/0000-0002-4741-9867

Kamil Emre GERÇEKASLAN

Food Engineering Department, Engineering and Architecture Faculty, Nevşehir Hacı Bektaş Veli University, Nevşehir, Turkey

*Corresponding author: naktas@nevsehir.edu.tr

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Figure 1
Block diagram of köftür production.

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Figure 2
Representative DSC curve of köftür samples from each other.

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Figure 3
Moisture adsorption isotherms of köftür samples at 5 °C, 15 °C and 25 °C.

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Figure 4
Isosteric heat of adsorption of the köftür.

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Table 1
Physicochemical, T_g and TPA characteristics of köftür samples.

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Table 2
Estimated parameters for several models for isotherms of köftür samples at different temperatures.

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Nomenclature aw water activity R2 determination coefficient Q n s t net isosteric heat of sorption (J/g) P mean relative percentage deviation Q s t isosteric heat of sorption (J/g) DSC Differential Scanning Calorimetry R universal gas constant (8.314 J/g K) Tg glass transition temperature T temperature (K) Tgo1 onset temperature of first transition (°C) Lr latent heat of vaporization of pure water (J/g) Tgm1 midpoint temperature of first transition (°C) BET Brunauer-Emmett-Teller Tge1 endset temperature of first transition (°C) GAB Guggenheim-Anderson-deBoer Tgo2 onset temperature of second transition (°C) m moisture content (kg water/100 kg dry matter) Tgm2 midpoint temperature of second transition (°C) mo monolayer moisture content for BET Tge2 endset temperature of second transition (°C) mm monolayer moisture content for GAB TPA Texture Profile Analysis a, b, c, k, n, p, A, B, C, D, K’, W, Wb constant parameters for the isotherm equations N Newton

(1)

(2)

(3)

(4)

Isotherm equation	a_w (range)	Temperature(°C)	Constant parameters	Determination coefficient (R²)	P (%)
Iglesias and Chirife	0.1-0.9	5	b= 2.74	0.949	0.27
$l n (m + {(m^{2} + m_{0.5})}^{\frac{1}{2}}) = p + b (a_{w})$		5	p= 2.08	0.949	0.27
		15	b= 2.61	0.947	0.30
		15	p= 2.02	0.947	0.30
		25	b= 2.38	0.948	0.29
		25	p= 2.04	0.948	0.29
Oswin	0.1-0.9	5	n= 0.56	0.907	21.33
$\ln m = \ln k + n l n (\frac{a_{w}}{1 - a_{w}})$		5	k= 14.86	0.907	21.33
		15	n= 0.54	0.924	16.23
		15	k= 13.25	0.924	16.23
		25	n= 0.50	0.930	14.11
		25	k= 12.06	0.930	14.11
BET	0.1-0.9 / 0.1-0.5	5	C=327/18.21	0.736/0.903	20.55/17.80
$\frac{a_{w}}{m (1 - a_{w})} = \frac{1}{(m_{o} c)} + \frac{(c - 1)}{(m_{o} c)} a_{w}$		5	m_o= 6.12/6.60	0.736/0.903	20.55/17.80
		15	C= -87.09/25.50	0.847/0.930	14.00/11.40
		15	m_o= 5.47/5.77	0.847/0.930	14.00/11.40
		25	C= -17.01/47.62	0.868/0.969	21.44/8.20
		25	m_o= 4.90/5.25	0.868/0.969	21.44/8.20
Harkins-Jura	0.1-0.9	5	A= 33.67	0.855	30.55
$\frac{1}{m^{2}} = (\frac{B}{A}) - (\frac{1}{A}) \log a_{w}$		5	B= -0.04	0.855	30.55
		15	A= 32.36	0.861	19.88
		15	B= -0.02	0.861	19.88
		25	A= 30.39	0.876	17.44
		25	B= -0.01	0.876	17.44
Smith	0.1-0.9	5	W= 20.78	0.965	17.78
$m = W_{b} - W l n (1 - a_{w})$		5	W_b= 1.63	0.965	17.78
		15	W= 19.09	0.978	16.66
		15	W_b= 0.56	0.978	16.66
		25	W= 15.48	0.983	12.80
		25	W_b= 1.52	0.983	12.80
Freundlich	0.1-0.9	5	n= 0.94	0.790	31.78
$\ln m = \ln k + \frac{1}{n} \ln a_{w}$		5	k= 38.73	0.790	31.78
		15	n= 0.94	0.763	36.22
		15	k= 38.73	0.763	36.22
		25	n= 0.94	0.766	41.56
		25	k= 38.73	0.766	41.56
Halsey	0.1-0.9	5	n= 1.30	0.925	22.33
$\ln m = [\frac{1}{n} \ln C] - (\frac{1}{n}) l n [\ln \frac{1}{a_{w}}]$		5	c= 20.78	0.925	22.33
		15	n= 1.35	0.960	12.68
		15	c= 20.28	0.960	12.68
		25	n= 1.46	0.967	10.67
		25	c= 23.55	0.967	10.67
GAB	0.1-0.9	5	m_m=7.27	0.625	22.00
$\frac{a_{w}}{m} = α a_{w}^{2} + β a_{w} + γ$			c=1.00
$m_{m} = {[\frac{- 1}{(4 α γ - β^{2})}]}^{\frac{1}{2}}$			K’=10.50
$C = [β - \frac{(\frac{1}{m_{m}})}{(- 2 γ)}]$		15	m_m=5.92	0.829	14.28
$K = \frac{1}{m_{m} C γ}$			c=1.00
			K’=26.39
		25	m_m=5.62	0.858	10.89
			c=0.97
			K’=31.09
Peleg	0.1-0.9	5	A= 52.08	0.934	10.73
$M = A a_{w}^{B} + C a_{w}^{D}$			B= 2.35
			C= 1.59
			D= -0.64
		15	A= 50.82	0.977	5.55
			B= 3.10
			C= 4.40
			D= -0.17
		25	A= 45.32	1.000	2.03
			B= 3.16
			C= 4.93
			D= -0.11
Modified Chung-Pfost	0.1-0.9	5	a= 95.38	0.946	30.89
$M = - \frac{1}{c} l n [\frac{(t + b) \ln (a_{w})}{- a}]$			b= 37.53
			c= 0.06
		15	a= 48.71	0.934	30.33
			b= 7.79
			c= 0.07
		25	a= 358.88	0.939	23.49
			b= 127.71
			c= 0.09
Modified Oswin	0.1-0.9	5	A= 9.03x10⁴	0.938	22.89
$M = (A + B t) {(\frac{a_{w}}{1 - a_{w}})}^{C}$			B= -1.80x10⁴
			C= 0.51
		15	A= 3.05x10⁴	0.972	14.87
			B= -2.03x10³
			C= 0.56
		25	A= 3.23x10⁴	0.979	11.72
			B= -1.29x10³
			C= 0.53

[1] *Corresponding author: naktas@nevsehir.edu.tr

pH	6.09±0.04
Titratable acidity (% citric acid)	0.08±0.06
Moisture (%)	33.96±0.13
Ash (%)	0.78±0.01
a_w	0.772±0.01
L*	25.89±0.22
a*	1.56±0.02
b*	6.42±0.06
T_go1 (°C)	-14.88±0.27
T_gm1 (°C)	-12.72±0.15
T_ge1 (°C)	-8.53±0.45
T_go2 (°C)	7.58±0.06
T_gm2 (°C)	24.50±0.19
T_ge2 (°C)	42.84±0.31

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Glass transition and sorption properties of Köftür: a dehydrated fruit-based product

Abstract