Rheological and melting properties of sucrose-free dark chocolate

In this study, sugar-free dark chocolate was produced from isomalt and maltitol by (V) seeding technique as an alternative to conventional tempering process. The effect of (V) seed concentrations on the particle size distribution (PSD), textural, rheological and melting properties of the final products were examined and the results were compared with those of conventional sugar-free dark chocolates. For this aim, conched dark chocolates were melted and crystallised with (V) seeds which were added at different concentrations (0.5, 0.6, 0.7, 0.8, 0.9 and 1.0%, m/m). According to the results PSD, hardness, rheological and melting properties were not influenced by seeding technique compared to conventional tempering method. On the other hand, inverse relation was observed between largest particle size and specific surface area of the samples. Hardness values of isomalt and maltitol including samples were found to change between 15.33-18.79N. Casson model best described the flow behaviour of the sugar-free chocolates. As a result, seeding technique can be used as an alternative method in sugar-free dark chocolate production in terms of quality and physical properties.Scientific and Technological Research Council of Turkey (TUBITAK)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [TOVAG-115O028]This work was funded by the Scientific and Technological Research Council of Turkey (TUBITAK), Project No. TOVAG-115O028

Sütlü Çikolata İçin Katı Faz Mikroekstraksıyon Yönteminin Optimizasyonu

In the current study, the Central Composite Design was applied to optimize HS-SPME extraction in orderto detect 2,3,5,6 tetramethyl pyrazine in isomalt contaning milk chocolate. The optimal conditions for thethree experimental responses influencing SPME efficiency were 10 min, 40 min and 57 °C for equilibrationtime, extraction time and extraction temperature, respectively. SPME fibers coated with 100 mpolydimethylsiloxane coating, 65 µm polydimethylsiloxane/divinylbenzene coating, 75 µmcarboxen/polydimethylsiloxane coating and 50/30 µm divinylbenzene/carboxen/polydimethylsiloxane ona StableFlex fiber were investigated. The preparation conditions of the chocolate samples were also evaluatedby measuring their effects on the coating composition of the head space. The SPME fiber coated with 50/30µm divinylbenzene/carboxen-polydimethylsiloxane provided the highest extraction efficiency, especiallywhen the samples were extracted at 60 °C for 30 min under dry conditions. Eighty-one blends were extractedand experimentally detected most of which have been formerly stated as odor-active components.Bu çalışmada, isomalt içeren sütlü çikolatalarda 2,3,5,6 tetra metal pirazin tayini için HS-SPME ekstraksiyonunun optimizasyonunda merkezi kompozit tasarım uygulanmıştır. SPME verimliliği etkileyen dengeleme süresi, ekstraksiyon süresi ve ekstraksiyon sıcaklığı için optimum koşullar olarak sırasıyla 10 dk, 40 dk ve 57 °C olarak belirlenmiştir. Çalışmada StableFlex fibere uygulanmış 100 µm polidimetilsiloksan, 65 µm polidimetilsiloksan/divinilbenzen, 75 µm karboksen/polidimetilsiloksan ve 50/30 µm divinilbenzen/karboksen/polidimetilsiloksan kaplamalar SPME fiberler olarak incelenmiştir. Çikolata örneklerinin hazırlama koşulları ayrıca tepe boşluğunun kaplama bi leşimi üzerindeki etkileri ölçülerek de değerlendirilmiştir. Özellikle örneklerin kuru koşullarda 60 °C’de 30 dk örnek ekstraksiyonunda 50/30 µm divinilbenzen/karboksen/polidimetilsiloksan kaplı SPME fiber en yüksek ekstraksiyon verimliliğini sağlamıştır

Lactic starter culture production technology

Starter kültür, fermantasyon sürecini hızlandırıp yönlendirerek istenen özelliklerde fermente gıda üretmek amacıyla hammaddeye katılan mikroorganizma kültürü olarak tanımlanabilir. Fermente gıda üretiminde en çok kullanılan mikroorganizmalar laktik asit bakterileridir. Laktik asit bakterilerinin starter kültür olarak kullanılabilmeleri için endüstriyel özellikleri iyi belirlenmelidir. Laktik asit bakterilerinin bakteriyofajlara duyarlılıkları, asit ve aroma bileşikleri oluşturma kabiliyetleri, bakteriyosin üretme potansiyelleri gibi endüstriyel öneme sahip özelliklerinin ayrıntılı olarak araştırılması gerekmektedir. Ticari starter kültür üretiminde kullanılan yöntemler üretim ve kalite açısından çok önemlidir. Piyasada satılan kültürler; üretim yöntemlerine bağlı olarak sıvı, toz (püskürterek kurutulmuş ve dondurarak kurutulmuş) ve dondurulmuş kültürler olmak üzere 3 temel formda üretilmektedir. Bu çalışmanın amacı starter kültürlerin seçim kriterleri ile üretim teknolojileri hakkındaki mevcut literatürü tarayarak bu alanda yapılacak olan çalışmalara katkı sağlamaktır.Starter culture can be defined as the microorganism culture that is added to the raw material in order to accelerate and manipulate the fermentation process to produce fermented food that had desired characteristics. The most commonly used microorganisms in fermented food production are lactic acid bacteria. The industrial properties of lactic acid bacteria must be well determined so that they can be used as starter cultures. The ability of lactic acid bacteria to susceptibility to bacteriophages, their ability to form acid and aroma compounds, and their potential to produce bacteriocin should be investigated in detail. The methods used in commercial starter culture production are very important in terms of production and quality. Cultures sold in the market; are produced in 3 basic forms as liquid, powder (spray-dried and freeze-dried) and frozen cultures depending on the production methods. The aim of this study is to contribute to the studies to be done on this field by searching the available literature on production technologies and selection criteria of starter cultures