Effects of fermented cereal germs and quinoa on quality of pasta

Name: Sonam Penjor

keyword: Amino Acids

MeSH: Amino acids

Classification :.DDC: e-Theses

; Rice Germ

MeSH: Fatty acids

MeSH: Antioxidants

MeSH: Lactic acid bacteria -- 105575

MeSH: Bacterial starter cultures -- 309114

LCSH: Amino acids

LCSH: Fatty acids

LCSH: Antioxidants

LCSH: Lactic acid bacteria -- 105575

LCSH: Bacterial starter cultures -- 309114

Abstract: Cereal germs and quinoa contain high nutritional values but their utilization is limited in the food industry and generally used as animal feeds. Pasta is a staple food consumed around the world. It is prepared with refined wheat flour that contains relatively low nutritional values. This study aimed to explore the possibility of the fermentation process enhancing the nutritional properties of underutilized cereal germs and quinoa. Wheat germ (WG), rice germ (RG), and quinoa (Q) were fermented by Lactobacillus plantarum TISTR 2074, and various analyses including physical and chemical properties of the fermented flour samples and the pasta fortified with fermented flour were investigated. WG, RG, and Q were ground and sieved through 500 nm. L. plantarum 2074 was cultured in de Man, Rogosa, and Sharpe (MRS) at 30°C for 12 hrs., and cells were harvested. The fermented flour was produced by mixing 200 g of germs or quinoa, 140 ml of distilled water, and cell suspension (20 ml) containing lactic acid bacteria (final cell density in the dough ca. 108 cfu/g) before fermentation for 24 hrs. at 30°C. Subsequently, the fermented flour was dried at 60°C until the moisture content reached below 10.5 %. The results showed that among the three types of raw material, the protein content was 30.88, 8.16, and 11.16 % and the fat content was 11.15, 4.04, and 6.31 % for WG, RG, and Q respectively (dry weight basis). Fermentation enhanced the protein content in all samples with the highest observed in the fermented wheat germ (FWG) being 37.40 % and reduced the carbohydrate in all samples. Fats, ash, and fiber were slightly significant differences (p < 0.05) in raw and fermented samples. The fatty acids were modified after fermentation in FRG and FQ but no significant difference (p ˃ 0.05) was indicated in WG. Palmitic acids reduced significantly (p < 0.05) in FQ from 23.54 to 13.70 %. Fermentation was also found to enhance amino acid (AA) content after fermentation. The essential AAs i.e. Val, Ile, Met, His, and Leu increased significantly (p ˂ 0.05) in all samples. In addition, total phenolic content (TPC) increased upon fermentation and subsequently, the antioxidant capacity of the fermented samples was also enhanced. The final viscosities and setback of all samples were reduced after fermentation, however, the peak viscosity (38.33 to 41.67) and breakdown (3.00 to 4.33) of WG slightly increased after fermentation. The second experiment showed the impact of fortifying fermented wheat germ (FWG), fermented rice germ (FRG), and fermented quinoa (FQ) flour at different concentrations (10%, 20%, and 30%) on the physicochemical properties and nutritional composition of the fresh pasta. The wheat pasta (WP) was made from 100% wheat flour as a control. Proximate analysis revealed that the addition of fermented flour increased protein and fiber content (p < 0.05), leading to enhanced nutritional value in all fortified samples compared to control pasta (WP, no fortification). Cooking properties, including optimum cooking time (OCT) and cooking loss (CL), were affected by fortification, with a reduction in OCT and an increase in CL. Color analysis showed alterations in L*, a*, and b* values. The L* was highest in WP (83.40) and lowest in W30 (66.61) whereas a* was found highest in W30 (4.86) indicating more redness and b* values which represent yellowness was found highest in W20 (25.27) and lowest in R10 (12.75). Water activity decreased in fortified pasta samples compared to control, potentially enhancing the shelf life of products. Fortification also significantly (p < 0.05) increased TPC and antioxidant properties, as measured by DPPH and FRAP assays. The highest TPC was observed in W30 (0.91 mg GAE/g), which also had the highest DPPH antioxidant properties at 156.41 mg GAE/g. The amino acid composition of all samples was mostly the lowest at 10% addition and increased as the fortification increased (20% and 30 %). Results revealed that fortification increased hardness from 258.99 g to 313.53 g for FWG and 179.83 g to 219.25 g for FQ while that in FRG decreased. In terms of sensory qualities, W30 showed the highest color and aroma score, while the highest taste score was obtained in R10, and WP had the best texture attribute. Overall, pasta acceptance was highest in W30 and lowest in Q10. The study highlights the potential of fortifying fresh pasta with fermented flour to enhance nutritional content, cooking properties, and antioxidant activity, providing insights for developing functional pasta products. It is noteworthy that the higher level of fortification (30%) had negative effects on hardness, color, and cooking loss. Lastly, 20% fortification of all fermented flour samples in pasta was chosen for the next experiment. Changes in pasta quality during storage at 4°C for 42 days were performed. Moisture content and water activity gradually declined during storage, while color analysis indicated the darker color of pasta progressed during the storage time. The cooking time and hardness of all samples decreased as the storage time increased, likewise, the cooking loss was pronounced, suggesting structural changes in the pasta matrix. Microbial analysis revealed an increase in total microbial counts and yeast and mold counts (YMC) over the storage period. The WP exceeded the set maximum bacterial number of 106 cfu/g after 28 days but the fortified sample could be stored for a longer time. The YMC of all samples was within the limit (5 log cfu/g) during storage. In conclusion, fermentation enhanced the nutritional properties of WG, RG, and Q, especially proteins, TPC, and antioxidant activities which improved the nutritional values of pasta products. The pasta developed by substituting 20% of FWG, FRG, and FQ showed good pasta properties as a cooking loss, hardness, and proteins were in the optimum range compared to 10% and 30% addition. Furthermore, the fortified pasta had longer storage periods based on the microbial properties compared to WP.

Mae Fah Luang University. Learning Resources and Educational Media Center

Address: CHIANG RAI

Email: library@mfu.ac.th

Name: Nattaya Konsue

Role: Advisor

Created: 2023

Modified: 2024-06-07

Issued: 2024-06-07

วิทยานิพนธ์/Thesis

application/pdf

CallNumber: e-Theses

eng

DegreeName: Master of Science

Level: Master's Degree

Descipline: Food Science and Technology

Grantor: Mae Fah Luang University

©copyrights Mae Fah Luang University

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