Flavor And Quality Change Of Chopped Chili In Hunan During Pickling

Capsicum annuum is a kind of important vegetable and condiment in people’s daily life. Chili is grown in two-thirds of the countries around the world. The production of chili in our country is the largest in the world. Chopped chili is the most common chili products in Hunan. In recent years, chopped chili was processed with high NaCl salted chili technology. As a result, there were many similar chopped chili products and also serious nutrient loss and environmental pollution in process. In order to maintain the traditional products characteristics in industrial process, this study was based on the main production process of chopped chili. With a view to the changes of characteristic volatile components on chopped chili, the physical and chemical change rules were explored under non-biological factors and biological factors, the correlation of material, process conditions and chopped chili quality were analyzed, which would provide theoretical basis and technology guidance for chopped chili production.The study was mainly about the change rules of main volatile components of chopped chili made by Chaotian Chili and Line Chili in different fermentation conditions. The research included:(1) change rules of tasty substances of chopped chili during natural fermentation (2) change rules of types and contents of organic acids of chopped chili in different fermentation conditions (3) change rules of volatile components of chopped chili during natural fermentation (4) effect of abnormal fermentation on tasty substances of chopped chili (5) effect of abnormal fermentation on volatile components of chopped chili (6) flavor and quality characteristics of chopped chili by high NaCl salted chili. Main conclusions were as follows:Total sugar and reducing sugar content of chopped chili decreased when added 10% NaCl during fermentation, while total acid and amino acid nitrogen content of chopped chili rose. The total sugar, reducing sugar, total acid, amino acid nitrogen (%) of chopped chili before fermentation were 3.62±0.06,3.25±.07,0.26±0.01 and 0.048±0.004. Total sugar, reducing sugar(%) in chopped chili were 1.92±0.06 and 1.79±0.08 after 4 weeks fermentation, with 47% and 45% consumption rate respectively. In addition, total acid, amino acid nitrogen (%) reached 0.59±0.03 and 0.158±0.006. Total sugar, reducing sugar, hardness Fmax of chopped chili compared with fresh chili decreased extremely significantly (P< 0.01), while total acid, and amino acid nitrogen increased extremely significantly (P< 0.01). Total sugar and reducing sugar content of chopped chili increased with increasing NaCl content (8%-12%), while total acid and amino acid nitrogen content of chopped chili gradually reduced, Fmax no significant change. The sensory quality of chopped chili became better by adding 8% to10% NaCl and 3-4 weeks fermentation.In the process of low NaCl content chopped chili, oil and sugar were the most commonly means to improve flavor in fermentation. Organic acids content of chopped chili added edible oil were less than that of blank control after fermentation 4 weeks, which indicated that adding edible oil was helpful to control chopped chili too sour. However, the total organic acid of chopped chili added sugar was higher than that of blank control, which had extremely significant difference (P< 0.01) between them. That was to say, sugar was beneficial to enhance chopped chili sour. The same kind of chili material, only different from inoculation fermentation and natural fermentation, its lactic acid, formic acid, acetic acid, succinic acid and total organic acid amount of chopped chili had significant differences (P<0.01). The types and contents of organic acid of the chopped chili had some fluctuations with the increase of fermentation time. Total organic acid reached the highest content in 3 weeks then decreased a little,In the process of natural fermentation, volatile components of chopped chili changed constantly.125 volatile components were identified during 1 to 4 weeks fermentation,. There were 103,95,84 and 97 volatile components respectively and 62 volatile components. Early fermentation stage raw green flavor substances rose. Then it reduced in the process of fermentation. Later, total numbers of volatile components reduced, more esters and acids were produced during further fermentation. In a word, esters numbers were the largest and the relative content of esters increased extremely significantly (P<0.01) in chopped chili. The results of principal components analysis (PCA) indicated that esters and aldehydes had positive correlation with chopped chili flavor. With 10% NaCl content, comprehensive scores of chopped chili were the highest after 4 weeks fermentation. This result was consistent with sensory evaluation conclusion.The consumption of total sugar and reducing sugar in 10% NaCl chopped chili, reached 63% and 62% respectively after 4 weeks sealed fermentation, while it reached 92% and 91% respectively during unsealed fermentation. Total acid, amino acid nitrogen content of chopped chili rose during sealed condition, which reached 0.71% and 0.15% respectively after 4 weeks fermentation. However, the opposite trend appeared during unsealed condition, total acid and amino acid nitrogen content of chopped chili decreased to 0.15% and 0.04% respectively. Total sugar, reducing sugar, total acid and amino acid nitrogen content of chopped chili had significant difference (P<0.05) between sealed and unsealed fermentation.With unsealed inoculation fermentation treatment, relative contents and numbers of phenols, esters, alcohols increased significantly, while olefin and aldehydes decreased significantly. Other volatile compounds almost remained unchanged. The relative content of phenols especially 4-ethyl guaiacol (4-EG) were over 20% in unsealed inoculation fermentation, which might had larger contribution to phenolic off-flavor (POF) in unsealed inoculation fermentation chopped chili for its low threshold value. PCA results showed that aldehydes, alcohols and acids in unsealed inoculation fermentation chopped chili had bigger correlation with the principal component 1, while phenols had bigger correlation with the principal component 2. In particular, aldehydes and alcohols had positively correlation, acids and phenols had negatively correlation.The amount of esters of chopped chili decreased, while alcohols and phenolics increased in long time sealed inoculation fermentation. Comprehensive scores of chopped chili was the highest in sealed inoculation,30℃ for 1 week fermentation. Long time inoculation fermentation and unsealed inoculation fermentation might make phenolics in chopped chili increase significantly.The best formula for keeping high NaCl salted chopped chili quality was that 23%NaCl, 0.09% citric acid,0.02% sodium metabisulfite and 0.20% calcium chloride.Total sugar, total acid, reducing sugar and amino acid nitrogen content of desalted chopped chili reduced significantly after desalination (P<0.05). Desalted chopped chili turned to be the best quality after the treatment of 6% Lactobacillus plantarum,4% sugar,30℃ fermentation for 5 days. The relative content of esters and aldehydes of desalted chopped chili increased significantly after inoculation fermentation, while alcohols and olefins decreased significantly. Inoculation fermentation helped to improve the flavor of chopped chili. The sensory quality of desalted chopped chili through fermentation or seasoning improved slightly, but still had certain gap with the traditional fermentation chopped chili.