Judul: Identification of aroma profiles two pineapple varieties and their new genotype using gas chromatography-mass spectrometry and gas chromatography-olfactometry and sensory test
Abstrak: Two varieties of pineapples, Mahkota Bogor, Delika Subang and their new genotype (Pasir Kuda), were freshly extracted using liquid-liquid extraction and solid phase microextraction (SPME). The aroma compounds of the three samples were analyzed by GC-MS and GC-olfactometry using nasal impact frequency (NIF) method. A total of 14 odor-active compounds were associated with the aroma of pineapple. Methyl 2-methyl butanoate and ethyl 2-methyl butanoate with very high intensity were found to be responsible for the pineapple fruity sweet odor. Other odorants including methyl hexanoate, ethyl hexanoate, methyl octanoate, methyl 3-(methylthio) propanoate, 2,5-dimethyl-4-methoxy-3(2H)- furanone, δ-hexalactone, γ-octalactone, 2,5-dimethyl-4-hydroxy-3(2H)-furanone and δ-decalactone contribute to the overall aroma of pineapple. The main differences between the aroma of Mahkota Bogor, Pasir Kuda and Delika Subang could be attributed to the olfactory attributes (fruity, sweet, caramel, pineapplelike, coconut) which were perceived by most of the panelist in the Mahkota Bogor and Pasir Kuda but were not detected in the Delika Subang samples. This work is a prerequisite for effective selection of pineapple genotypes with optimal aroma profiles for high consumer acceptance.
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Judul: Profil Sensori dan Preferensi Buah Mangga Arumanis, Bacang, Indramayu, Gedong, dan Kweni serta Korelasinya dengan nilai L dan oHue
Abstrak: Mangga adalah buah tropis yang banyak tumbuh dengan beragam jenis di Indonesia. Buah ini memiliki flavor dan warna khas yang menjadi daya tarik bagi konsumen. Penelitian ini bertujuan untuk memperoleh profil sensori aroma dan rasa terkait preferensi konsumen terhadap buah mangga Arumanis, Bacang, Indramayu, Gedong, dan Kweni serta korelasinya dengan nilai L (kecerahan) dan oHue. Profil sensori deskripsi ditentukan melalui uji sensori metode QDA sedangkan preferensi konsumen ditentukan dengan uji sensori metode uji rating hedonik. Uji warna ditentukan menggunakan Chromameter. Profil sensori ditentukan oleh 15 panelis terseleksi sedangkan preferensi konsumen oleh 70 panelis umum. Hasil QDA menunjukkan bahwa 5 sampel mangga terbagi atas 2 kelompok. Kelompok pertama adalah Arumanis, Gedong, dan Indramayu dengan deskripsi sensori rasa manis, dan aroma fruity, honey, juicy, mango, ripe, sweet. Kelompok kedua adalah Bacang dan Kweni dengan deskripsi sensori rasa asam, sepat, pahit, dan aroma lemon, starchy, woody. Mangga yang memiliki preferensi paling tinggi ialah varietas Indramayu dengan skor 5 (agak suka). Korelasi antara nilai kecerahan dan oHue dengan profil sensori dan preferensi konsumen ditentukan dengan uji korelasi Pearson menggunakan SPSS. Nilai L (kecerahan) berkorelasi positif dengan profil sensori atribut rasa asam, sepat, pahit dan aroma starchy namun berkorelasi negatif dengan preferensi konsumen atribut sensori aroma, rasa, dan overall. Nilai oHue (derajat warna) berkorelasi positif dengan profil sensori atribut aroma juicy, honey, dan mango serta berkorelasi positif dengan preferensi konsumen atribut rasa dan overall.
Keyword: flavor, mangga, sensori, warna

Judul: A Continuous Vaccination Strategy in the SVIR Epidemic Model
Abstrak: Vaccination is conducted to minimize the spread of a disease. The vaccination is usually done several times within a fixed time interval. In the SVIR model, it is assumed that individuals do not get immediate immunity following a vaccination program. So according to process of vaccination on SVIR model, there are two strategies, i.e. the continuous vaccination strategy (CVS) and the pulse vaccination strategy (PVS). In this study, only the CVS strategy in epidemic model SVIR is considered. Results of the study indicate that dynamics of the CVS system depends on the basic reproductive number. If the basic reproductive number is less than one, then the disease-free fixed point is asymptotically stable. It means that the disease will eventually disappear from the population. Conversely, if the basic reproductive number is greater than one, then the endemic fixed point is asymptotically stable, which means that the disease will remain exist in the population. Simulation result shows that the vaccination would minimize the spread of disease by reducing the basic reproductive number. If the time for the vaccinated recipients to obtain the immunity, as well as a possibility of vaccinated recipients to be infected are neglected, then the disease will be eradicated. This condition is called an over-evaluating effect of vaccination.
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