Optimisation of important processing conditions for rice bran sourdough fermentation using Lactobacillus plantarum

The potentials of rice bran sourdough in bread making are recently gaining popularity. However, there is no information on the influence of processing conditions on the quality attributes of rice bran sourdough. To inves- tigate the influence of fermentation time and temperature on the levels of acidity (pH and TTA) in rice bran sour- dough fermented with L. plantarum, we applied response surface methodology (RSM). Furthermore, we studied the effect of different fermentation time and temperature on the total phenolic and volatile compounds in the sourdough. GC/MS measurements for the evolution of aroma volatile compounds (VOCs) in the rice bran sourdoughs were conducted. The higher and longer the fermentation temperature and time, the higher the acidity levels in the sour- doughs. Fermentation temperature and time do not have a significant effect on the total phenolic sourdough con- tents. Forty-seven VOCs were detected in the rice bran sourdoughs. The major VOCs were acetic acids, ethanol, 2-Methoxy-4-vinylphenol, Hexadecanoic acid, 1-(hydroxymethyl)-1,2-ethanediyl ester, acetoin, and 2-methoxy-Phe- nol. The sourdough fermented at 35°C for 13 ho contained the largest number (27) of aroma compounds and had the highest acidity. These fermentation conditions are close to the optimal parameters (temperature – 33°С, duration – 12.5 hours), obtained as a result of applying RSM for rice bran fermentation. Thus, high quality bran sourdough can be produced at the temperature of 33°C for 12.5 hours. The results of this study will be useful to produce a quality rice bran sourdough bread with appealing aroma and a long shelf-life

Physicochemical Properties of Morinda Citrifolia Fruits and Leaves Produced by Oven and Freeze Drying

Morinda citrifolia, also known as Noni, is a nutritional plant that contains beneficial characteristics and has been explored in both the pharmaceutical and food industrial fields. This study was carried out to compare the physicochemical properties of Noni fruits and leaves powder produced by freeze-drying and oven drying methods. Oven drying was carried out at different temperatures (50 °C, 60 °C, and 70 °C) while the freeze-drying method was carried out at constant temperature (-50 °C) and time (40 hours). The physicochemical properties (antioxidant, moisture content, water activity, density, water solubility, and color) of the fruits and leaves powder were analyzed. Freeze-drying produced the lowest moisture content and water activity of Noni fruit and leaf powder. The study revealed that increased in oven drying temperature decreased the color properties (L*, a*, b*), moisture content and water solubility of both Noni fruit and leaves powder. Bulk and tapped density showed slightly changes with an increase in drying temperature. Oven dried Noni fruit and leaf powder at 50 °C had the highest percentage of DPPH radical scavenging activity. Besides, freeze-drying proved to have better physicochemical properties in Noni fruits and leaves. The results obtained indicate a significant difference between the physicochemical properties of freeze dried Noni fruits and leaves powder in terms of water activity, color, and DPPH radical scavenging activity

Influence of starter culture on the physicochemical properties of rice bran sourdough and physical quality of sourdough bread

The effect of mixed strain culture of lactic acid bacteria (LAB) and Yeast, and yeast or L. brevis, L. plantarum, or L. sanfranciscencison the physicochemical properties (pH, TTA, organic acid, ethanol, and sugar content) of rice bran sourdough was investigated. Starter culture with optimum physicochemical properties was used to ferment rice and wheat bran for sourdough production. Rice and wheat bran sourdough and non-fermented rice and wheat bran were mixed with wheat flour at 10% substitution level for bread production. Results showed that rice bran fermented with L. plantarumhad the best physicochemical properties compared to rice bran sourdough produced by other LAB or mixed culture. The specific volume of bread sample made with rice bran sourdough (4.65 cm3/g) was higher than that of the bread samples made from wheat bran sourdough (4.32 cm3/g) and non-fermented bran (3.74 –4.24 cm3/g), but not significantly different from the control (100% wheat) bread (4.85 cm3/g). The crumb colour of the rice bran and rice bran sourdough substituted bread was lighter than that of the other bread samples. Crust colour of all the bread samples was not significantly different (p > 0.05). At the end of 6 days storage period, bread samples from control and wheat bran sourdough were firmer than that from rice bran sourdough, however, crumb firmness values were highest in non-fermented bran substituted bread. Sensory analysis result revealed that rice bran sourdough bread was more acceptable than wheat bran sourdough bread, and non-fermented rice and wheat bran substituted bread

Effect of Tapioca and Potato Starch on the Physical Properties of Boiled Keropok Lekor

Keropok lekor is a traditional Malay snack that originated from Terengganu, Malaysia. Fish and sago starch are the two main ingredients in the production of keropok lekor that greatly affect the texture and taste of keropok lekor. In this study, the impact of incorporating tapioca starch (TS), potato starch (PS) and a mixture of tapioca and potato starch (TS:PS) into the formulation was investigated with regards to the physical properties of boiled keropok lekor. The physical properties evaluated including colour, moisture content, water holding capacity, linear expansion, cooking yield and texture of the boiled keropok lekor. The addition of tapioca and/or potato starch had no impact on colour of keropok lekor. However, their usage caused a significant reduction in moisture content and cooking yield as compared to the control keropok lekor (made with only sago starch). Potato starch substantially enhanced water holding, while a mixture of tapioca and potato starch led to a decrease in the linear expansion of boiled keropok lekor. This study demonstrates that application of these starches influences the quality of boiled keropok lekor and their impact is expected to be more pronounces when frying the boiled keropok lekor

Physicochemical characteristics of rice bran sourdough fermented with Lactobacillus plantarum for breadmaking

A general growing awareness of healthy lifestyle increased the interest of the food industry in the market of high fiber products. Rice bran, an agro-byproduct obtained from outer rice layers, could offer a new variety of baked goods with high fiber content. However, bran supplementation usually can cause severe problems to the quality of final products. Thus, supplementation with bran requires changes in processing techniques for the production of baked goods with good consumer quality. One of the techniques being employed is fermentation and this study was carried out to optimize the fermentation conditions of rice bran sourdough. This was then followed by evaluation of the rice bran sourdough functionality. Rice bran used in this study contained 10.9% moisture, 16.1% fat, 12.7% protein, 8.8% ash, 22.4% insoluble dietary fiber, 1.3% soluble dietary fiber and 27.8% carbohydrate. The use of lactic acid bacteria (LAB) and yeast starter cultures in the fermentation process resulted in slight differences among the fermentative end product characteristics of the sourdough. These characteristics were highly influenced by the LAB strains used. Lactobacillus plantarum was better than Lactobacillus brevis and Lactobacillus sanfranciscencis at producing the desired pH, total titratable acidity (TTA), organic acids, fermentation quotient and soluble sugars required in sourdough preparation. A response surface methodology (RSM) and central composite design (CCD) were employed to obtain the optimum fermentation conditions for obtaining acidic properties and antioxidant phenolic compounds in rice bran sourdough incorporated with Lactobacillus plantarum. The acidity values found showed that the fermentation temperature and time at 33°C and 12.5 hours, respectively, were able to produce optimum pH (pH 3.5 to 4.5) and total titratable acidity (16 to 22 ml of 0.1M NaOH). Total phenolic compounds increased in parallel with increasing fermentation temperature and time. Rice bran sourdough gave breads with significantly higher loaf specific volume (4.65cm3/g) and crumb softness (3.54) compared to rice bran bread and wheat bran sourdough bread. Sourdough was able to maintain the freshness and prolong shelf life of the bread. Supplementation of the bread dough with bran darkened the final product. Rice bran sourdough bread got the lowest score, in terms of overall acceptance, when compared to wheat bran sourdough, rice bran, wheat bran and control (no bran) breads in sensory evaluations

Properties of cereal brans: a review

Cereal brans are functional ingredients with high nutritive value and enormous health properties. Cereal brans have not been fully utilized in food systems despite their health benefits. This review presents an overview on the physical, chemical, microbiological, functional, and sensory properties of cereal brans for possible comparisons and selection to enhance the utilization of this underutilized milling fraction