Optimasi Masa Simpan Yogurt Kering Terfortifikasi Zymomonas mobilis dan Gelombang Ultraviolet dengan Variasi Kadar Asam Laktat dan Suhu

Prawoto, Marisa Aurelia (2024) Optimasi Masa Simpan Yogurt Kering Terfortifikasi Zymomonas mobilis dan Gelombang Ultraviolet dengan Variasi Kadar Asam Laktat dan Suhu. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Penelitian ini dilakukan dengan tujuan sebagai studi komparasi antara masa simpan dari dua jenis yogurt yang telah difortifikasi dengan bakteri Z. mobilis kemudian dikeringkan dengan metode liofilisasi. Pada yogurt pertama (disebut sebagai varian YKZ), yogurt hanya diberi perlakuan berupa fortifikasi Z. mobilis dan liofilisasi, sementara pada yogurt kedua (disebut sebagai varian YKZ-UV) diberikan perlakuan tambahan yaitu radiasi ultraviolet jenis C (UVC). Adapun aspek yang dinilai adalah perubahan pH dan total asam tertitrasi (TAT) selama masa uji coba yakni 14 hari. Kedua jenis subjek penelitian tersebut disimpan dalam 3 suhu yang berbeda: 4ºC, 25ºC, dan 38ºC. Selain itu, dilakukan pula uji organoleptik untuk menilai kualitas fisik yogurt. Kualitas yang dinilai meliputi warna, rasa, aroma, dan tekstur yogurt. Subjek penelitian dibuat dengan bahan utama berupa susu sapi segar komersil yang dipasteurisasi, kultur yogurt Z. mobilis hasil regenerasi di lab, serta starter yogurt komersil yang mengandung bakteri Lactobacillus bulgaricus, Lactobacillus acidophillus, Lactobacillus plantarium, Lactobacillus casei, dan Streptococcus thermophilus. Dari hasil uji pH dan TAT, didapatkan bahwa kedua yogurt mengalami penurunan nilai pH dan kenaikan persentase asam laktat selama 14 hari masa uji coba walaupun tidak terlalu signifikan. Nilai pH YKZ lebih rendah dibandingkan dengan yogurt YKZ-UV, sementara kadar persentase asam laktatnya lebih tinggi dibanding yogurt YKZ-UV. Data juga menunjukkan, makin tinggi suhu penyimpanan, probabilitas terjadinya degradasi pH dan keasaman yogurt makin besar terjadi. Yogurt yang disimpan pada suhu 4ºC jadi varian yang paling stabil, baik pada yogurt YKZ maupun YKZ-UV. Degradasi ini berjalan sebanding dengan suhu penyimpanan, dibuktikan dengan perhitungan Accelerated Shelf-Life Testing dengan pendekatan model Arrhenius. YKZ-UV memiliki masa simpan yang lebih lama dibandingkan dengan YKZ.
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The purpose of this research was to conduct a comparative study on the shelf life of two types of yogurt fortified with Z. mobilis bacteria and subsequently dried using the lyophilization method. In the first yogurt variant (referred to as YKZ), the yogurt underwent fortification with Z. mobilis and lyophilization, while the second variant (referred to as YKZ-UV) received an additional treatment involving Ultraviolet C (UVC) radiation. The assessed aspects included changes in pH and total titratable acidity (TAT) over a 14-day testing period. Both types of research subjects were stored at three different temperatures: 4ºC, 25ºC, and 38ºC. Furthermore, organoleptic tests were conducted to assess the physical quality of the yogurt, encompassing color, taste, aroma, and texture. The research subjects were formulated using main ingredients such as commercial pasteurized fresh cow's milk, Z. mobilis yogurt culture regenerated in the lab, and a commercial yogurt starter containing Lactobacillus bulgaricus, Lactobacillus acidophilus, Lactobacillus plantarum, Lactobacillus casei, and Streptococcus thermophilus bacteria. From the pH and TAT test results, it was observed that both yogurts experienced a decrease in pH value and an increase in the percentage of lactic acid over the 14-day testing period, although not significantly pronounced. The pH value of YKZ was lower compared to YKZ-UV, while its percentage of lactic acid was higher than that of YKZ-UV. Data also indicated that with higher storage temperatures, there was a greater probability of yogurt pH degradation and increased acidity. Yogurt stored at 4ºC demonstrated the most stability, both in YKZ and YKZ-UV variants. This degradation was directly proportional to the storage temperature, as evidenced by Accelerated Shelf Life Testing calculations using the Arrhenius model approach. YKZ-UV exhibited a longer shelf life compared to YKZ.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	Yogurt, Liofilisasi, Z. mobilis, ASLT, Gelombang UVC, Yogurt, Lyophilization, Z. mobilis, ASLT, UVC Wave
Subjects:	Q Science > QD Chemistry > QD251.2 Chemistry, Organic. Biochemistry
Divisions:	Faculty of Science and Data Analytics (SCIENTICS) > Chemistry > 47201-(S1) Undergraduate Thesis
Depositing User:	Marisa Aurelia Prawoto
Date Deposited:	16 Feb 2024 06:21
Last Modified:	16 Feb 2024 06:21
URI:	http://repository.its.ac.id/id/eprint/107236

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