Jelatinin Fonksiyonel Özellikleri ve Gıda Sanayinde Kullanımı

Gelatin is a protein based food additive derived by thermal denaturation from the collagen, which is the main and structural protein of animal tissues. Gelatin is a water soluble material produced by some processes included the disruption of tertiary, secondary and partially primary structures of collagen. Gelatin, is an important hydrocolloid at high molecular weight which is produced from the animal skin, white connective tissues and bones. It is used at wide range in food industry because of its gelling and thickening capabilities. The most important differences of gelatin from the other hydrocolloids are its thermos reversible melting characteristic at below the human body temperature, being derived as a natural protein by animal sources and being an additive at GRAS status. At this review, it is aimed to explain the conventional and alternative sources for gelatin manufacturing, the functional properties, melting and gelling properties, the surface properties of gelatin and consequently, it is aimed to explain also the wide usage of gelatin in food industry related its specific properties.

Properties and Microstructures of Sn-Bi-X Lead-Free Solders

The Sn-Bi base lead-free solders are proposed as one of the most popular alloys due to the low melting temperature (eutectic point: 139°C) and low cost. However, they are not widely used because of the lower wettability, fatigue resistance, and elongation compared to traditional Sn-Pb solders. So the alloying is considered as an effective way to improve the properties of Sn-Bi solders with the addition of elements (Al, Cu, Zn, Ga, Ag, In, Sb, and rare earth) and nanoparticles. In this paper, the development of Sn-Bi lead-free solders bearing elements and nanoparticles was reviewed. The variation of wettability, melting characteristic, electromigration, mechanical properties, microstructures, intermetallic compounds reaction, and creep behaviors was analyzed systematically, which can provide a reference for investigation of Sn-Bi base solders.

A Primary Study of Torch Brazing Pure Aluminum with Al-Si-Ge-Zn Solders

Based on the difficulty to accurately control temperature for torch brazing, the study is concerned with developing low-melting-point solders for brazing pure aluminum. For this purpose, Ge and Zn have been chosen to be added to Al-Si-based alloy. The melting characteristic, wetting property of solders with Al and mechanical property of the brazed joints were investigated. The results show that the addition of 10 wt. % germanium into the traditional Al-12Si (wt. %) filler metal causes its liquidus temperature to decrease by about 23 °C. An addition of 30 % zinc into such Al-Si-Ge ternary alloy will cause its liquidus temperature to drop further to 525 °C. The solders have good wettability with Al. With the increase of Zn content in the alloys, the spreading areas of solders exhibit nonlinear decrease, and there exist a very large value at the zinc content of 15%. When Al-Si-10Ge-30Zn solder was used to braze the pure aluminum, an optimized bonding strength of 116 MPa was achieved.