Identification of Microbial Flora in Dry Aged Beef to Evaluate the Rancidity during Dry Aging

Dry aging creates a unique taste and flavor in beef; however, the process also causes rancidity, which is harmful to humans. During dry aging, the microbial flora in beef changes continuously; thus, this change can be used as an indicator of rancidity. The objective of this study was to analyze the correlation between microbial flora in beef and rancidity during dry aging. The round of beef (2.5–3 kg) was dry aged under 1.5 ± 1 °C and 82 ± 5% moisture for 17 weeks. The microflora in the dry aged beef was analyzed by pyrosequencing. The volatile basic nitrogen (VBN) and thiobarbituric acid reactive substance (TBARS) values were also measured. Primers were designed to detect and quantify bacteria using real-time polymerase chain reaction (RT-PCR). The VBN and TBARS values in the dry aged beef depreciated from week 11 of aging. The levels of Streptococcus spp., Pantoea spp., and Pseudomonas spp. significantly changed at around week 11. Quantitative RT-PCR showed that the levels of Pantoea spp. and Streptococcus spp. could be used to identify rancidity during dry aging. Thus, among the microbial flora in dry aged beef, Pantoea spp. and Streptococcus spp. can be used to determine the rancidity of dry aged beef.

Ảnh hưởng của cao chiết từ ba loài nấm ăn đến khả năng chống oxy hoá dầu cá

Nghiên cứu được thực hiện nhằm mục đích khảo sát khả năng chống oxy hóa của cao chiết từ ba loài nấm ăn, nấm rơm (Volvariella volvacea), bào ngư (Pleruotus sajor-caju) và kim châm (Flammulina velutipes), từ đó ứng dụng cao chiết trong bảo quản các sản phẩm thủy sản. Cao chiết từ ba loài nấm được chiết trong nước ở 95 ± 2oC trong 1 giờ. Hoạt tính chống oxy hóa của cao chiết từ các loài nấm ăn được đánh giá thông qua khả năng khử gốc tự do 2,2-diphenylpicrylhydrazyl (DPPH) và tổng hàm lượng phenolic. Cao chiết từ các loài nấm ăn được bổ sung vào dầu cá hồi nhằm đánh giá khả năng chống oxy hóa ở nhiệt độ 60oC thông qua việc xác định chỉ số peroxide (PV) và thiobarbituric acid reactive substance (TBARS). Kết quả cho thấy khả năng khử gốc tự do DPPH (IC50) tăng dần từ nấm rơm, nấm bào ngư xám, gốc nấm và thân nấm kim châm lần lượt là 618 µg/mL, 919 µg/mL, 1114 µg/mL và 1354 µg/mL. Tổng hàm lượng phenolic của cao chiết giảm dần từ nấm rơm, gốc nấm kim châm, nấm bào ngư xám và thân nấm kim châm lần lượt là 0,60 mgGAE/100mg; 0,51 mgGAE/100mg; 0,43 mgGAE/100mg và 0,23 mgGAE/100mg cao chiết. Cao chiết từ ba loài nấm ăn có thể được sử dụng để bảo quản dầu cá hồi, thể hiện thông qua khả năng chống oxy hóa của chúng trong...

Formaldehyde and De/Methylation in Age-Related Cognitive Impairment

Formaldehyde (FA) is a highly reactive substance that is ubiquitous in the environment and is usually considered as a pollutant. In the human body, FA is a product of various metabolic pathways and participates in one-carbon cycle, which provides carbon for the synthesis and modification of bio-compounds, such as DNA, RNA, and amino acids. Endogenous FA plays a role in epigenetic regulation, especially in the methylation and demethylation of DNA, histones, and RNA. Recently, epigenetic alterations associated with FA dysmetabolism have been considered as one of the important features in age-related cognitive impairment (ARCI), suggesting the potential of using FA as a diagnostic biomarker of ARCI. Notably, FA plays multifaceted roles, and, at certain concentrations, it promotes cell proliferation, enhances memory formation, and elongates life span, effects that could also be involved in the aetiology of ARCI. Further investigation of and the regulation of the epigenetics landscape may provide new insights about the aetiology of ARCI and provide novel therapeutic targets.

Determination of acrolein in ambient air and in the atmosphere of environmental test chambers

Acrolein (2-propenal) is a reactive substance undergoing multiple reaction pathways and an airborne pollutant with known corrosive, toxic and hazardous effects to the environment and to human health. So far,...

Penurunan malondialdehyde serum setelah latihan interval dan continuous di pagi hari pada perempuan obesitas

Penelitian ini bertujuan untuk menganalisis penurunan malondialdehyde (MDA) setelah latihan interval dan continuous di pagi hari pada perempuan obesitas. Penelitian ini adalah true experiment dengan rancangan penelitian a Basic Time Series Design dengan menggunakan subjek 27 perempuan obesitas usia 20-25 tahun, body mass index (BMI) 25-35 kg/m2, percentage body fat (PBF) di atas 30% dan VO2max 25-35 ml/kg/min dan secara random dibagi menjadi tiga kelompok, yaitu CON (n=9, kontrol tanpa intervensi), MIE (n=9, moderate interval exercise) dan MCE (n=9, moderate continuous exercise). Intervensi dilakukan di pagi hari pukul 07.00-09.00 WIB. Intervensi MIE dan MCE dilakukan selama 40 menit menggunakan treadmill. Pengambilan sampel darah dilakukan pre-exercise, 10 menit dan 6 jam post-exercise. Pengukuran serum MDA menggunakan metode Thiobarbituric Acid Reactive substance (TBARs). Teknik analisis data menggunakan uji ANOVA dan LSD post hoc test dengan Statistic Package for Social Science (SPSS) versi 21. Serum MDA menurun signifikan setelah 10 menit dan 6 jam pasca intervensi MIE dan MCE (P<0.05), tetapi tidak pada CON (P>0.05). Berdasarkan hasil penelitian disimpulkan bahwa serum MDA menurun setelah 10 menit dan 6 jam pasca intervensi MIE dan MCE dibandingkan dengan CON pada perempuan obesitas. Tetapi pola penurunan serum MDA pada MCE lebih rendah dibandingkan dengan MIE dan CON.

AKTIVITAS ANTIOKSIDAN EKSTRAK IKAN GABUS (Channa striata) PADA TIKUS YANG DIINDUKSI DENGAN RIFAMPISIN-ISONIAZID

Antioksidan merupakan substansi yang diperlukan untuk menetralisir radikal bebas dan mencegah kerusakan sel normal, protein, dan lemak. Radikal bebas berlebih dalam tubuh menyebabkan stres oksidatif. Salah satu parameter stres oksidatif adalah meningkatnya kadar malondialdehid (MDA). Ekstrak ikan gabus berperan sebagai antioksidan. Penelitian dilakukan untuk mengetahui efek pemberian suplemen ekstrak ikan gabus sebagai antioksidan pada tikus yang mendapatkan obat rifampisin-isoniazid dosis tinggi. Tikus dikelompokan menjadi 4 yaitu kelompok I (kontrol), kelompok II (ekstrak ikan gabus), kelompok III (rifampisin-isoniazid), dan kelompok IV (rifampisin-isoniazid dan ekstrak ikan gabus). Kadar MDA dalam darah diukur menggunakan metode Tiobarbiturat Acid Reactive Substance (TBARS) dengan spektrofotometer UV-Vis 532 nm. Analisis data menggunakan uji Anava dan uji Kruskal Wallis. Hasil analisis kadar rata-rata MDA darah dan hati kelompok I, II, III, dan IV berturut-turut pada darah 0.67±0.12; 0.38±0.20; 4.01±1.57; 2.68±1.72 μg/mL, dan hati 3.73±0.80; 2.96±1.94; 31.31±4.45; 17.69±10.55 μg/g. Hasil menunjukkan kadar MDA darah kelompok III dan IV signifikan terhadap kelompok II, pada hati kelompok III signifikan terhadap kelompok I dan II sedangkan kelompok IV signifikan terhadap kelompok I, II, dan III. Suplemen ekstrak ikan gabus dosis tinggi berpotensi sebagai antioksidan pada tikus yang mengalami stres oksidatif.

Pengaruh Pemberian Infusa Daun Kerokot terhadap Kadar MDA (Malondialdehida) pada Hewan Coba

Tanaman kerokot (Lygodium microphylum) menunjukan adanya aktivitas antioksidan dengan nilai IC50 65 µ.g/ml. Tujuan penelitian ini untuk mengetahui senyawa metabolit sekunder yang terkandung dalam daun kerokot dan mengetahui pengaruh pemberian infusa daun kerokot terhadap malondialdehida (MDA) pada hewan coba yang telah dipaparkan asap rokok. Digunakan metode TBARS (Thiobarbituric Acid Reactive Substance) yang diukur menggunakan Spektofotometer UV-Vis untuk menganalisis kadar MDA. Hewan coba sebanyak 20 ekor dibagi 4 kelompok yaitu kelompok kontrol normal, paparan asap rokok selama 7 hari, kelompok paparan asap rokok 14 hari serta kelompok infusa daun kerokot. Hasil fitokimia menunjukan bahwa infusa daun kerokot mengandung flavonoid dan tanin. Pengujian kadar MDA menunjukan hasil penurunan kadar MDA setelah pemberian infusa daun kerokot dosis 600 mg/kg BB.