Perpustakaan Unika
PENGARUH KOMPOSISI BAHAN BAKU, KEMASAN, DAN SUHU
PENYIMPANAN TERHADAP SIFAT FISIKOKIMIA, SENSORIS DAN MIKROBIOLOGIS MINUMAN SARI BUAH JAMBU BIJI MERAH (Psidium guajava Linn)
THE EFFECTS OF RAW MATERIAL COMPOSITION, PACKAGING AND STORAGE TEMPERATURE ON THE PHYSICAL, CHEMICAL, SENSORY AND MICROBIOLOGICAL PROPERTIES OF GUAVA JUICES (Psidium guajava Linn)
SKRIPSI Diajukan untuk memenuhi sebagian syarat – syarat guna memperoleh gelar Sarjana Teknologi Pangan Disusun oleh : Liely Saridewi Hartono 03.70.0110
PROGRAM STUDI TEKNOLOGI PANGAN FAKULTAS TEKNOLOGI PERTANIAN UNIVERSITAS KATOLIK SOEGIJAPRANATA SEMARANG 2007
Perpustakaan Unika
DAFTAR ISI RINGKASAN…………………………………………………………………………………......i SUMMARY………………………………………………………………………………………..... ii KATA PENGANTAR…………………………………………………………………..... iii DAFTAR ISI..........................................................................................................................v DAFTAR TABEL................................................................................................................vii DAFTAR GAMBAR..........................................................................................................viii DAFTAR LAMPIRAN.........................................................................................................ix 1. PENDAHULUAN............................................................................................................1 1.1. Jambu Biji..................................................................................................................1 1.2. Sari Buah...................................................................................................................3 1.3. Umur Simpan Sari Buah............................................................................................5 1.4. Tujuan Penelitian.......................................................................................................7 2. MATERI DAN METODE................................................................................................8 2.1. Materi.........................................................................................................................8 2.2. Metode.......................................................................................................................8 2.2.1. Pembuatan Sari Buah Jambu Biji Merah........................................................8 2.2.2. Penelitian Utama...........................................................................................13 2.2.3. Analisa Kimia...............................................................................................14 2.2.3.1. Pengukuran Nilai pH........................................................................14 2.2.3.2. Pengukuran Kandungan Vitamin C..................................................14 2.2.4. Analisa Fisik.................................................................................................14 2.2.4.1. Pengukuran Viskositas.....................................................................14 2.2.4.2. Pengukuran Warna...........................................................................14 2.2.4.3. Analisa Total Solid...........................................................................15 2.2.5. Analisa Mikrobiologis..................................................................................15 2.2.5.1. Angka Lempeng Total......................................................................15 2.2.6. Analisa Sensoris...........................................................................................16 2.2.7. Analisa Umur Simpan..................................................................................16 2.2.8. Analisa Data.................................................................................................16 3. HASIL PENELITIAN....................................................................................................17 3.1. Pengujian Kimiawi..................................................................................................17 3.1.1. Analisa pH....................................................................................................17 3.1.2. Analisa Kandungan Vitamin C.....................................................................20 3.2. Pengujian Fisik........................................................................................................23 3.2.1. Analisa Viskositas........................................................................................23 3.2.2. Analisa Warna (Pencoklatan Non Enzimatis)..............................................26 3.2.3. Analisa Total Solid.......................................................................................29
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Perpustakaan Unika
4. 5. 6. 7.
3.3. Analisa Mikrobiologis............................................................................................32 3.3.1. Analisa Angka Lempeng Total....................................................................32 3.4. Analisa Sensoris.....................................................................................................34 PEMBAHASAN...........................................................................................................37 KESIMPULAN.............................................................................................................42 DAFTAR PUSTAKA...................................................................................................43 LAMPIRAN.................................................................................................................46
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Perpustakaan Unika
RINGKASAN Buah-buahan merupakan bahan pangan sumber vitamin. Selain buahnya yang dimakan dalam bentuk segar, kulitnya juga dapat digunakan untuk berbagai keperluan. Warna buah cepat sekali berubah oleh pengaruh fisika misalnya sinar matahari dan pemotongan, serta pengaruh biologis (jamur) sehingga mudah menjadi busuk. Oleh karena itu pengolahan buah untuk memperpanjang masa simpannya sangat penting. Salah satu pengolahan buah adalah pembuatan sari buah. Sari buah adalah cairan yang dihasilkan dari pemerasan atau penghancuran buah segar yang tidak dimasak. Jambu biji adalah salah satu tanaman buah jenis perdu, dalam bahasa latin disebut Psidium guajava Linn. Diantara berbagai jenis buah, jambu biji mengandung vitamin C yang paling tinggi dan sebagian besar vitamin C jambu biji terdapat pada kulit dan daging buah. Penelitian ini bertujuan untuk mengetahui pengaruh komposisi bahan baku sari buah, kemasan, dan suhu penyimpanan terhadap sifat fisikokimia, sensoris, dan mikrobiologis sari buah jambu biji merah. Jambu biji yang digunakan dalam penelitian ini adalah jambu biji berdaging merah. Komposisi bahan baku sari buah yang digunakan adalah daging buah (tanpa kulit buah) dan jambu utuh (beserta kulitnya). Kemasan yang digunakan adalah botol kaca dan cup plastik polypropilene. Sari buah jambu biji merah ini disimpan pada suhu kamar (27-30ºC) dan suhu refrigerasi (4,5-7oC) selama 15 hari penyimpanan. Parameter pengamatan kualitas minuman sari buah jambu biji merah yaitu analisa kimia (uji pH dan kandungan vitamin C), analisa fisik (viskositas, intensitas warna, total solid), uji sensoris, serta uji mikrobiologis (angka lempeng total). Selama 15 hari penyimpanan terjadi penurunan nilai pH dan kandungan vitamin C pada sari buah jambu biji merah dengan berbagai komposisi bahan baku sari buah, kemasan, dan suhu penyimpanan. Viskositas, intensitas warna, dan total solid meningkat selama 15 hari penyimpanan pada sari buah jambu biji merah dengan berbagai komposisi bahan baku sari buah, kemasan, dan suhu penyimpanan. Dari hasil penelitian diketahui bahwa sari buah dengan kemasan botol kaca memiliki umur simpan lebih panjang daripada sari buah dengan kemasan cup plastik polypropilene. Sedangkan sari buah yang disimpan pada suhu kamar memiliki masa simpan lebih pendek daripada sari buah yang disimpan pada suhu refrigerasi. Sari buah dengan komposisi bahan baku jambu utuh memiliki kandungan vitamin C lebih tinggi daripada sari buah yang terbuat dari daging buah saja. Kata kunci : sari buah jambu biji, kemasan, komposisi bahan baku, suhu penyimpanan
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Perpustakaan Unika
SUMMARY Fruits are food stuff rich in vitamins. Other than their freshly edible meat, fruit skin can also be used for many purposes. Fruit color is easily affected by physical effects such as sun light and any incisions and also by biological influence that they rot. Therefore further treatments to lengthen fruit’s duration are required. One of the methods is to make them juices. Juices are products of crushing and pressing of untreated fruit. Guava (Psidium guajava Linn) is one of the fruit that contain high amount of vitamin C and most of it is contained within its meat and skin. This research is aimed at figuring out the effects of raw material composition, packaging and storage temperature on the physical, chemical, sensory and microbiological properties of guava juices. The guavas used in this research are those with red meat. And two compositions were used. One with only its meat (without the skin) and the other is the whole fruit (with its skin). The packages used were glass bottles and polypropylene plastic cups. These guava juices were then kept at room temperature (27-30oC) and at refrigerator temperature (4.5-7oC) for 15 days of storage. The parameters used to analyze the quality of these juices are chemical analyses (pH test and vitamin C content), physical analyses (viscosity, color intensity, total solid), sensory tests, and microbiological tests (total plate number). After 15 days of storage, pH value and vitamin C content decrease were observed in those juices of many different types of composition, packaging and storage temperature, whereas their viscosity, color intensity and total solid were increased. Results indicate that juices in glass bottles can be kept much longer than those in polypropylene plastic cups. While those kept at room temperature have shorter shelf life than the ones kept at refrigerator temperature. In addition, juices made of whole fruit composition contain higher vitamin C than those made of only fruit meat. Keyword : Guava juice, types of composition, packaging, storage temperature
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