Wyniki wyszukiwania - BazTech

1

Potential Application of Used Coffee Grounds in Leather Tanning

Nasr Ahmed I., El Shaer Mohammed A., Abd-Elraheem Mohamed A.

Journal of Ecological Engineering

|

2023

|

Vol. 24, nr 3

10--19

EN

Safety of environment and human health is an essential requirement of modern industrial techniques. Therefore, using natural agents in tanning industry may emerge as a trusted method to avoid the chemical contamination caused by using traditional chromium salts in tanning process. This study aimed to evaluate the hot water extract of used coffee grounds (UCGs) as a vegetable tanning agent. The collected UCGs were dried and extracted with hot water at 90 °C for 2h. The phytochemical screening properties of UCGs extract were determined. Sufficient amount of extract was prepared to be used in leather tanning. Three groups were tanned with UCGs extract solely at concentrations of 20, 30 or 40% of pelts’ weight, while another three groups were tanned with the same concentrations and then re-tanned with 10% of a synthetic tanning agent “Phenol sulfonates”. On tanned leathers, organoleptic, physical and chemical properties were determined; scanning electron micrographs were depicted to examine the leather surface and collagen fiber bundles. Analysis of UCGs extract revealed that it has good tanning properties, as it contained tannins (14.92%), tannins/non tannins ratio (2.06), hide powder (39.57) and Stiasny number (21.16). The results of leather properties showed that using UCGs extract alone at concentration of 40% achieved the best results for the vegetable tanning where the tanned leather had higher (P<0.05) tensile strength, tearing strength and shrinking temperature than that treated with the lower level of 20% UCGs extract. However, 40% of UCGs extract is highly recommended to be used to accomplish the required shrinkage temperature that should be ≥ 70 °C. UCGs extract could be successfully used as tanning agent in vegetable tanning to produce durable leathers with good fullness; it may be used for different manufacturing products, such as footwear and bags. Moreover, using a combination of UCGs extract at any of the used concentrations with phenol sulfonates 10% led to significant improvement in all studied traits as compared with using UCGs extract alone.

2

Comparison of the content of selected bioactive compounds in infusions of different teas®

Waszkiewicz-Robak Bożena

Postępy Techniki Przetwórstwa Spożywczego

|

2021

|

nr 1

63--71

EN

The purpose of this paper is to compare the content of total extracts, caffeine, tannins and total polyphenolic compounds in infusions of different teas from the same region of cultivation. The antioxidant properties of the infusions prepared from these teas have also been determined. The research material consisted of Chinese leaf teas purchased in a chain of hypermarket stores in Warsaw. They included: green tea, a mixture of green and white tea and black tea. It has been indicated that the type of tea has a significant impact on the content of polyphenols, tannins and caffeine, and the brewing time significantly changes the content of tannins in the infusions. The extract content in tea infusions depends to a large extent on the concentration of the prepared infusions and is the reflection of their strength. For all teas tested, the antioxidant activity of infusions depended on the content of polyphenolic compounds and was significantly higher for green tea infusions and green tea blends.

PL

Celem artykułu jest porównanie zawartości substancji wyciągowych ogółem, kofeiny, garbników oraz związków polifenolowych ogółem w naparach różnych herbat pochodzących z tego samego rejonu upraw. Oznaczono również właściwości przeciwutleniające naparów sporządzonych z tych herbat. Materiał badawczy stanowiły chińskie herbaty liściaste zakupione w sieci hipermarketów w Warszawie. Były to: herbata zielona, mieszanka herbat zielonej z białą oraz herbata czarna. Wykazano, że rodzaj herbaty ma istotny wpływ na zawartość związków polifenolowych, garbników i kofeiny, a czas parzenia istotnie zmienia zawartość garbników w naparach. Zawartość substancji wyciągowych w naparach herbat zależy istotnie od stężenia przygotowanych naparów i jest odzwierciedleniem ich mocy. Dla wszystkich badanych herbat aktywność przeciwutleniająca naparów zależała od zawartości związków polifenolowych i była istotnie wyższa dla naparów z herbaty zielonej i mieszanki herbaty zielonej z białą.

3

Effect of Black Cherry (Prunus serotina) Litter Extracts on Germination and Growth of Scots Pine (Pinus sylvestris) Seedlings

Bączek Paulina, Halarewicz Aleksandra

Polish Journal of Ecology

|

2019

|

Vol. 67, nr 2

137--147

EN

In the managed forest of temperate Europe, black cherry (Prunus serotina) is one of the most important invader species. Among the ecological traits enabling its expansion in forest stands, the role of chemical compounds released naturally by this plant into the environment still remains unclear. The aim of this study was to determine the influence of black cherry leaf litter on the germination and growth of Scots pine (Pinus sylvestris) seedlings. Laboratory bioassays with extracts from newly fallen and decomposed leaves showed a phytotoxic effect on root elongation and a slightly weaker negative effect on stem growth of pine shoots. The inhibitory effect increased with the gradient of leaf extract concentration. Furthermore, a significant negative correlation was observed between condensed tannin content in decomposed leaf litter of the black cherry and the pine root growth. The results are discussed in the context of black cherry litter properties which could interfere with natural regeneration of pine forests.

4

Green synthesis of silver nanoparticles using tannins

Raja P B, Rahim A A, Qureshi A K, Awang K

Materials Science Poland

|

2014

|

Vol. 32, No. 3

408--413

EN

Colloidal silver nanoparticles were prepared by rapid green synthesis using different tannin sources as reducing agent viz. chestnut (CN), mangrove (MG) and quebracho (QB). The aqueous silver ions when exposed to CN, MG and QB tannins were reduced which resulted in formation of silver nanoparticles. The resultant silver nanoparticles were characterized using UV-Visible, X-ray diffraction (XRD), scanning electron microscopy (SEM/EDX), and transmission electron microscopy (TEM) techniques. Furthermore, the possible mechanism of nanoparticles synthesis was also derived using FT-IR analysis. Spectroscopy analysis revealed that the synthesized nanoparticles were within 30 to 75 nm in size, while XRD results showed that nanoparticles formed were crystalline with face centered cubic geometry.