Effects of coagulating enzyme types (commercial calf rennet, Aspergillus niger var. awamori as recombinant chymosin and rhizomucor miehei as microbial rennet) on the chemical and sensory characteristics of white pickled cheese

The possibilities of using recombinant chymosin as an alternative coagulant to commercial calf rennet in the production of white pickled cheese was investigated. For this purpose, white pickled cheese produced by using commercial calf rennet, recombinant chymosin (Aspergillus niger var. awamori) and microbial rennet (Rhizomucor miehei) were compared in terms of their chemical and organoleptic properties. The cheese samples were stored in brine containing 12% salt at 4±1°C for 60 days. In the study, which was carried out in duplicate, pH, titratable acidity, dry matter, fat, fat-in-dry matter, protein, salt, nitrogeneous compounds (water sobuble nitrogen (WSN), ripening index (RI), non-protein nitrogen (NPN), electrophoretic and organoleptic properties of the cheese samples were determined at 1, 15, 30 and 60 days of storage. According to the results, the effects of enzyme type on the titratable acidity, dry matter, salt, nitrogeneous compounds and all sensory properties, except for the odour was significant (p<0.05). At the end of storage, the titratable acidity, salt, WSN, RI, NPN values and sensory scores of the cheeses increased, while the pH, fat, total nitrogen (TN), protein, b- and as1-casein contents of cheeses decreased compared to initial values.Keywords: White pickled cheese, calf rennet, recombinant chymosin, microbial rennet.African Journal of Biotechnology Vol. 12(37), pp. 5588-559

A novel metaheuristic for traveling salesman problem: blind mole-rat algorithm

Gezgin Satıcı Problemi (GSP), başlangıç ve bitiş şehirleri aynı olan ve her şehrin sadece bir kez ziyaret edildiği minimum mesafeli turu bulma problemidir. Şehir sayısı arttıkça, kesin yöntemler ile kabul edilebilir sürelerde bir optimum çözüm bulunması zordur. Bu nedenle, son elli yılda GSP’nin çözümü için doğadan ve biyolojiden esinlenen birçok meta-sezgisel yöntem geliştirilmiştir. Bu çalışmada, toprak altındaki bireysel tünel sistemlerinde yaşayan kör farelerin toprak altındaki engelleri geçme stratejisinden esinlenilerek GSP’nin çözümü için yeni bir meta-sezgisel tasarlanmıştır. Geliştirilen yönteme Kör Fare Algoritması adı verilmiştir. Bu yeni sezgisel ile farklı boyutlardaki simetrik test veri setleri için deneyler yapılmış ve sonuçları bilinen en iyi sonuçlar ile kıyaslanmıştır. Önerilen meta-sezgisel henüz literatürdeki diğer algoritmalarla yarışabilecek düzeyde olmamasına rağmen, başlangıç test çözümlerinin umut verici olduğu söylenebilir.Traveling Salesman Problem (TSP) is the problem of finding a minimum distance tour of cities beginning and ending at the same city and that each city are visited only once. As the number of cities increases, it is difficult to find an optimal solution by exact methods in a reasonable duration. Therefore, in recent five decades many heuristic solution methods inspired of nature and biology have been developed. In this paper, a new metaheuristic method inspired of the by-passing the obstacle strategy of blind mole rats living in their individual tunnel systems under the soil is designed for solving TSP. The method is called as Blind Mole-rat Algorithm. The proposed algorithm is tested on different size of symmetric TSP problems and the results are compared to the best known results. Initial test results are promising although proposed metaheuristic is not yet competitive enough among other algorithms in the literature