scholarly journals Natural Drying of Astringent and Non-Astringent Persimmon “Rojo Brillante”. Drying Kinetics and Physico-Chemical Properties

Foods ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 647
Author(s):  
Cristina M. González ◽  
Rebeca Gil ◽  
Gemma Moraga ◽  
Alejandra Salvador

Persimmon (Diospyros kaki L.f.) crop has markedly increased in Spain, and “Rojo Brillante” persimmon is the main cultivated variety. This astringent cultivar requires de-astringency treatment before commercialization, which may involve an extra cost. Its short commercial season implies handling large volumes of fruits with consequent postharvest losses. Therefore, the development of derived added-value products is of much interest. In this study, astringent and non-astringent “Rojo Brillante” persimmons were dehydrated by following a natural drying method used in Asia. The drying kinetics and physico-chemical properties were analyzed for 81 days. The results indicated subsequent reductions in weight, water content, and water activity throughout the drying process, and the equatorial diameter decreased. All the employed thin-layer mathematical models were suitable for representing the drying characteristics of both products with similar behavior. The effective water diffusivity values were 5.07 × 10−11 m2 s−1 and 6.07 × 10−11 m2 s−1 for astringent and non-astringent persimmon samples, respectively. The drying treatment significantly decreased the soluble tannins content, and the astringent samples obtained similar values to those obtained for the non-astringent samples in 20 days. The external and internal flesh of the astringent fruit remained orange through the drying period, while brown coloration in the non-astringent fruit was observed after 57 drying days. Therefore, prior de-astringency treatment would not be necessary.

Foods ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 788
Author(s):  
João Paulo de Lima Ferreira ◽  
Alexandre José de Melo Queiroz ◽  
Rossana Maria Feitosa de Figueirêdo ◽  
Wilton Pereira da Silva ◽  
Josivanda Palmeira Gomes ◽  
...  

The residue generated from the processing of Tacinga inamoena (cumbeba) fruit pulp represents a large amount of material that is discarded without proper application. Despite that, it is a raw material that is source of ascorbic acid, carotenoids and phenolic compounds, which are valued in nutraceutical diets for allegedly combating free radicals generated in metabolism. This research paper presents a study focused on the mathematical modeling of drying kinetics and the effect of the process on the level of bioactive of cumbeba residue. The experiments of cumbeba residue drying (untreated or whole residue (WR), crushed residue (CR) and residue in the form of foam (FR)) were carried out in a fixed-bed dryer at four air temperatures (50, 60, 70 and 80 °C). Effective water diffusivity (Deff) was determined by the inverse method and its dependence on temperature was described by an Arrhenius-type equation. It was observed that, regardless of the type of pretreatment, the increase in air temperature resulted in higher rate of water removal. The Midilli model showed better simulation of cumbeba residue drying kinetics than the other models tested within the experimental temperature range studied. Effective water diffusivity (Deff) ranged from 6.4890 to 11.1900 × 10−6 m2/s, 2.9285 to 12.754 × 10−9 m2/s and 1.5393 × 10−8 to 12.4270 × 10−6 m2/s with activation energy of 22.3078, 46.7115 and 58.0736 kJ/mol within the temperature range of 50–80 °C obtained for the whole cumbeba, crushed cumbeba and cumbeba residue in the form of foam, respectively. In relation to bioactive compounds, it was observed that for a fixed temperature the whole residue had higher retention of bioactive compounds, especially phenolic compounds, whereas the crushed residue and the residue in the form of foam had intermediate and lower levels, respectively. This study provides evidence that cumbeba residue in its whole form can be used for the recovery of natural antioxidant bioactive compounds, mainly phenolic compounds, with the possibility of application in the food and pharmaceutical industries.


2020 ◽  
Vol 66 (No. 3) ◽  
pp. 89-96
Author(s):  
Chibuzo Nwankwo ◽  
Chigozie Francis Okoyeuzu ◽  
Ikpeama Ahamefula

The efficiency of three modified plastic digesters (3.6 m<sup>3</sup> each) using food waste for biogas generation in cooking food was evaluated. The experiment was laid out based on a completely randomised design. A plastic tank was modified as a biodegradation system for food waste digestion to generate a biogas. The biochemical and chemical oxygen demand ranged from 44.58 to 49.62% and 130.42 to 139.20%, respectively, before digestion, but decreased significantly (P &lt; 0.05) after digestion. The pH of the fermenting slurry fluctuated (6.24–6.86) and an average biogas of 0.574 m<sup>3</sup> (505–601 L·day<sup>–1</sup>) per day was generated from the three experimental waste proportions which would be sufficient to cook three meals per day for 3 to 4 people. The methane gas significantly increased (P &lt; 0.05) while the carbon-dioxide significantly decreased (P &lt; 0.05) at the peak of the biogas production. The generated biogas significantly cooked (P &lt; 0.05) faster than kerosene, but not faster than liquefied petroleum gas. The flammable biogas generation and high significant (P &lt;0.05) percentage change in the physico-chemical properties of the wastes after digestion implied high efficiency performance of the digesters modified from the plastic tanks.


1993 ◽  
Vol 28 (8-9) ◽  
pp. 139-147 ◽  
Author(s):  
K. T. Valsaraj ◽  
G. J. Thoma ◽  
C. L. Porter ◽  
D. D. Reible ◽  
L. J. Thibodeaux

Natural colloids are part of the carbon cycle arising from sediment diagenesis. Natural colloids can be quantified as the dissolved organic carbon (DOC) present in the pore-water of sediment beds. In this paper we demonstrate that DOC is mobile in a system in which the dominant transport mechanism is Brownian diffusion. A simple model which assumes constant physico-chemical properties for the DOC adequately predicts the DOC release rate from a sediment bed in a microcosm. A single adjustable parameter, the water diffusivity, is used to fit the model to the experimental data. The experimental diffusivities obtained from the fitted data agree well with previously presented values.


Molecules ◽  
2020 ◽  
Vol 25 (18) ◽  
pp. 4123 ◽  
Author(s):  
Philippe M. Loiseau ◽  
Sébastien Pomel ◽  
Simon L. Croft

The control of leishmaniases, a complex parasitic disease caused by the protozoan parasite Leishmania, requires continuous innovation at the therapeutic and vaccination levels. Chitosan is a biocompatible polymer administrable via different routes and possessing numerous qualities to be used in the antileishmanial strategies. This review presents recent progress in chitosan research for antileishmanial applications. First data on the mechanism of action of chitosan revealed an optimal in vitro intrinsic activity at acidic pH, high-molecular-weight chitosan being the most efficient form, with an uptake by pinocytosis and an accumulation in the parasitophorous vacuole of Leishmania-infected macrophages. In addition, the immunomodulatory effect of chitosan is an added value both for the treatment of leishmaniasis and the development of innovative vaccines. The advances in chitosan chemistry allows pharmacomodulation on amine groups opening various opportunities for new polymers of different size, and physico-chemical properties adapted to the chosen routes of administration. Different formulations have been studied in experimental leishmaniasis models to cure visceral and cutaneous leishmaniasis, and chitosan can act as a booster through drug combinations with classical drugs, such as amphotericin B. The various architectural possibilities given by chitosan chemistry and pharmaceutical technology pave the way for promising further developments.


2018 ◽  
Vol 11 (6) ◽  
pp. 1236-1247 ◽  
Author(s):  
Baoguo Xu ◽  
Benxi Wei ◽  
Xiaofeng Ren ◽  
Yaogang Liu ◽  
Hao Jiang ◽  
...  

Author(s):  
H. Gross ◽  
H. Moor

Fracturing under ultrahigh vacuum (UHV, p ≤ 10-9 Torr) produces membrane fracture faces devoid of contamination. Such clean surfaces are a prerequisite foe studies of interactions between condensing molecules is possible and surface forces are unequally distributed, the condensate will accumulate at places with high binding forces; crystallites will arise which may be useful a probes for surface sites with specific physico-chemical properties. Specific “decoration” with crystallites can be achieved nby exposing membrane fracture faces to water vopour. A device was developed which enables the production of pure water vapour and the controlled variation of its partial pressure in an UHV freeze-fracture apparatus (Fig.1a). Under vaccum (≤ 10-3 Torr), small container filled with copper-sulfate-pentahydrate is heated with a heating coil, with the temperature controlled by means of a thermocouple. The water of hydration thereby released enters a storage vessel.


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