Kakao yağının serbest yağ asitliği düzeyini etkileyen proses parametrelerinin incelenmesi
Investigation of process parameters affecting the level of free fatty acid of cocoa butter
Yazar: BÜŞRA ÇİÇEK
Danışman: PROF. DR. NEŞE ŞAHİN YEŞİLÇUBUK
İstanbul Teknik Üniversitesi / Lisansüstü Eğitim Enstitüsü / Gıda Mühendisliği Ana Bilim Dalı / Gıda Mühendisliği Bilim Dalı
Derece: Yüksek Lisans, 2023
Konu: Gıda Mühendisliği = Food Engineering

Özet:
Ham kakao yağında yüksek miktarda bulunan serbest yağ asitleri (SYA) yağın deodorize edilmesi ile belli bir seviyeye düşürülür. Daha yüksek SYA içeriğinin, kakao yağının sertliğinde bir azalmaya yol açtığı ve hem üreticiler hem de çikolata üreticileri için ham kakao ticari değerini azaltan bir faktör olduğu düşünülmektedir. Hem yağın kalitesini arttırmak hem de yasal sınırlara uygun hale getirmek için çeşitli proseslerle SYA kontrol altında tutulmalıdır. 
Bu çalışmada, kakao yağı üretiminde SYA'ya etki edecek debakterizasyon, kavurma ve deodorizasyon proseslerindeki debakterizasyon sıcaklığı ve süresi, kavurma alt-üst sıcaklıkları, deodorizasyon sıcaklığı, süresi, buhar basıncı ve vakum değerleri değişkenlerinin etkisinin istatistiksel yöntemlerle incelenmesi amaçlanmıştır.Yapılan veri analizine göre anlamlı bulunan değişkenler deodorizasyon süresi, deodorizasyon vakum değeri ve çok sayıdaki verinin medyanı alınarak analiz edilen kavurma üst sıcaklığı olmuştur (p ≤ 0,05).
Deodorizasyon sıcaklıkları 150-174 °C arasında değişmiş olup, SYA'ya etki etmemiş ve anlamlı değişken olarak gözlemlenmemiştir. Bunun yanı sıra deodorizasyonda kullanılan buhar basıncı/miktarı SYA değişiminde efektif bir değişken olarak gözlemlenmemiştir (p> 0,05).  Kakao yağını oluşturmak için birden fazla kakao çekirdeği partileri kavrularak birleştirilir, veri analizindeki farklı partilerin kavurma sıcaklık dağılımları geniş skalada olduğundan ortalama alınarak elde edilen tek veride, istatistiksel analize göre değişken anlamlı bulunmamıştır (p> 0,05).  Medyan alınarak elde edilen kavurma verilerinde ise sadece üst sıcaklık anlamlı çıkmıştır (p ≤ 0,05). Kavurmanın üst sıcaklıkları nemin uzaklaştırılması amacı ile kullanılırken, kavurmanın alt sıcaklıklarında ise aroma ve renk oluşturma işlemlerinin yapılmasından dolayı kavurma alt sıcaklıklarında SYA değişimi minimal düzeyde olmuştur ve kavurma alt sıcaklığı SYA'yı etkileme noktasında anlamlı çıkmamıştır. Debakterizasyon proses aşamasında uygulanan sıcaklıklar 250℃ altında ve işlem süresi saniye düzeyinde olduğundan SYA  uzaklaştırılması minimal düzeyde olmakta  ve etki düzeyi düşük olduğundan SYA'yı etkileme noktasında anlamlı bulunamamıştır (p> 0,05). 
Çalışmanın sonucuna göre, debakterizasyon süresi arttırılarak prosesin devamında SYA için stabilizasyon durumunun arttırılabileceği ve deodorizasyon sıcaklıkları da 200 °C ve üzerine çıkarılarak uzaklaştırılan SYA arttırılarak proses veriminin arttırılabileceği tespit edilmiştir.

Abstract:
The harvest of the cocoa is done twice a year, once in May and the other in October or November. Because not all seeds mature at the same time, the harvest can be spread over several months. In the production of cocoa bean, after the cocoa bean is separated from the fleshy part, it is fermented by making a heap, and drying process is applied after fermentation. Cocoa beans are cleaned from foreign materials such as stone, wood and metal. Afterwards, steam is given at a certain pressure, temperature and time to reduce the bacterial load, thereby reducing the bacterial load and eliminating the risk of Salmonella. The roasting process is carried out in order to create a certain color, aroma and reduce the humidity. In order to reveal the nib inside the roasted kernel, the crushing process is applied and the shells are removed. Afterwards, the nibs separated from the shell are grinded with a mill to form cocoa liquor. When cocoa liquor is pressed, cocoa butter and cocoa cake are separated from each other. Cocoa butter obtained in raw form is exposed to the deodorization process and its quality is improved and the stability of the oil is increased by reducing the level of Free Fatty Acids (FFA) thanks to the deodorization process. The higher FFA content is thought to lead to a reduction in the hardness of cocoa butter and is a factor that reduces the commercial value of raw cocoa for producers and chocolate producers. FFA should be kept under control with various processes in order to both increase the quality of the oil and comply with the regulatory values.
The FFA content strongly influences the basic technological properties of the oil, changes the solidification kinetics and significantly softens the cocoa butter. It also has a negative effect on crystallization processes such as tempering. Due to such quality defects, the maximum FFA content in cocoa butter is limited to a value of 1.75% (as oleic acid). To meet the acceptable level of 1.75% in cocoa butter extracted from cocoa beans, the free fatty acids (FFA) content of ingested cocoa beans is expected to be less than 1.0. The temperature, time, humidity, lipase activity, mold, physical stress exposed during the cocoa bean processing process affect the FFA level.
In this study, it is aimed to examine the effects of the variables of debacterization temperature and time, roasting bottom and top temperatures, deodorization temperature, time, steam pressure and vacuum values in debacterization, roasting and deodorization processes that will affect FFA in cocoa butter production by statistical methods. The variables found were deodorization time, deodorization vacuum value and roasting top temperature analyzed by taking the median of many data (p ≤ 0.05).
The effect of temperature and duration applied in debacterization processes on FFA level was emphasized in all studies. In the basic mechanism, if the free fatty acids are removed by vacuuming or different removal methods by creating moisture with superheated steam, the FFA ratio in the product decreases, but if moisture removal is not performed, the FFA ratio in the product increases.
Studies in the literature indicate that the FFA value decreases with the increase in the temperature applied for roasting the cocoa bean. There are different opinions about the application time of the roasting temperature, some studies state that the time has no effect, while others state that the increase in time reduces FFA.
When the studies in the literature for deodorization are examined, it can be concluded that the FFA removed by increasing the temperature and increasing the vacuum value at temperatures of 200°C and above will be higher, the effect of the amount of steam given by FFA is very small, and it is not related to the time.
Vacuum, steam pressure, deodorization temperature, deodorization time and FFA distributions in the deodorization process dataset used in the regression analysis were shared. Vacuum values are 0-6 mbar, vapor pressure 10.5-11.5 bar, deodorization temperature 150-174 ⁰C, deodorization time varies between 50-100 minutes (min), while FFA values vary between 0.88-3.15%. Deodorization temperatures varied between 150-174 °C, did not affect FFA. Therefore, it were not observed as a significant variable. In addition, the vapor pressure/amount used in deodorization was not observed as an effective variable in FFA change (p> 0.05). 
During the roasting process of cocoa beans, different temperatures are applied in the lower and upper parts of the roaster. A cocoa butter batch is formed by combining more than one cocoa bean batch after roasting. Therefore, there is more than one roasting temperature data in a batch. In order to apply the regression on a single data set, the medians and averages of more than one roasting temperature data in a batch were taken and regression was applied as 2 separate sets. FFA distributions were shared with the roasting sub-temperature process data set, which was created by taking the median and average used in the regression analysis. While the lower roasting temperatures formed by taking the median and its average vary between 130-159 ⁰C, the FFA values vary between 0.88-3.15%. In order to form cocoa butter, more than one cocoa bean batches are roasted and combined. Since the roasting temperature distributions of different batches in the data analysis are on a wide scale, the variable was not found to be significant according to the statistical analysis in the single data obtained by averaging (p> 0.05). In the roasting data obtained by taking the median, only the upper temperature was significant (p ≤ 0.05). While the upper temperatures of roasting are used to remove moisture, the change in FFA was minimal at the lower temperatures of roasting due to the aroma and color formation processes at the lower temperatures of roasting, and the lower roasting temperature was not significant in affecting FFA. 
In the debacterization process of cocoa beans, heat treatment is applied with steam. The temperature and duration of the applied steam vary. A cocoa butter lot is formed by combining more than one cocoa bean lot by debacterizing. Therefore, there is more than one debacterization temperature and time in a batch. In order to apply the regression on a single data set, regression was applied as 2 separate sets by taking the medians and averages of the data of more than one debacterization temperature and time in a batch. The debacterization temperatures, which were created by taking the median and average used in the regression analysis, were shared with the process data set and FFA distributions. While the debacterization temperatures formed by taking the median and the average ranged between 208-246 ⁰C, the FFA values ranged between 0.88-3.15%. Debacterization times, which were created by taking the median and average used in the regression analysis, were shared with the process data set and FFA distributions. The median debacterization times vary between 5-7.5 seconds (sec), while the averaged ones vary between 5-8 seconds (sec), and FFA values vary between 0.88-3.15%. Since the temperatures applied in the debacterization process stage are below 250°C and the processing time is in seconds, FFA removal is minimal, and since the effect level is low, it was not found to be significant in affecting FFA (p> 0.05).
With the data obtained from this study, it is thought that it will be possible to provide both enzyme inactivation by increasing the debacterization time and to ensure the removal of free fatty acids by increasing the diffusion of moisture with the given steam, and stabilization for FFA will increase in the continuation of the process. In future studies, it is recommended to conduct new studies to examine the effects of deodorization temperatures of 200 °C and above on FFA removal and the quality changes of the oil during this time.