Guava

Cara sitasi: Ramadhan W, Trilaksani W. 2017. Formulasi hidrokoloid-agar, sukrosa dan Acidulant pada pengembangan produk selai lembaran. Jurnal Pengolahan Hasil Perikanan Indonesia 20(1): 95-108. Abstrak Penggunaan agar-agar tepung sebagai texturizer dalam pemanfaatan jambu biji merah (Psidium guajava L.) sebagai single selai lembaran menjadikan produk selai lebih praktis dalam penyajiannya. Penelitian ini bertujuan untuk menentukan formulasi sukrosa, asam sitrat (acidulant) dan agar-agar tepung terbaik pada pembuatan selai lembaran. Metode penelitian yang digunakan adalah optimasi dan formulasi sukrosa, asam sitrat dan agar-agar dengan kosentrasi berbeda dalam pembuatan selai lembaran. Pengujian fisikokimia dan sensori dilakukan untuk menentukan formula selai lembaran terbaik, selain itu metode bayes digunakan untuk menentukan optimasi formula terpilih. Formulasi dan pengujian diperoleh selai jambu biji lembaran dengan konsentrasi Acidulant asam sitrat (0,02%, 0,04%, 0,06%), sukrosa (70%, 80%, 90%, 100%) dan agar-agar tepung (0,7%, 0,8%, 0,9%, 1,0%, 1,1%, 1,2%), memiliki nilai pH 3,63-3,90; kadar gula 34,68-35,76 g/100 g; intensitas warna L*, a*, b* dengan perbedaan warna (ΔE*) 37,88-53,97; kadar serat 1,01%-1,59%; dan nilai aw 0,852-0,893. Sifat rheology selai lembaran untuk profil tekstur hardness, cohesiveness, springiness, adhesive force, dan gumminess juga menunjukkan nilai yang signifikan dengan penambahan tepung agar. Hasil uji Bayes, produk terpilih merupakan formulasi terbaik dengan penambahan gula 90%, asam sitrat 0,04% dan agar-agar tepung 0,9%. Selai lembaran terpilih menghasilkan model persamaan umur simpan Arrhenius ln k = 20,222-6660,6 (1/T) dan memiliki angka kecukupan gizi dengan menyumbangkan energi total 45 kkal, lemak 0%, karbohidrat 9%, protein 2% dan serat pangan 3%. Kata kunci: agar-agar tepung, profil tekstur, rheologi, selai jambu biji lembaran Abstract Tallying agar powder as a texturizer in guava single sheet jam instigate the product more convenience to consumed. The aims of this research were to determine the best concentration of sucrose, citric acid and agar powder to form a good quality guava jam slice. The research method are optimization and formulation of sucrose, citric acid and agar-agar on making guava jam single sheets product. Physochemical and sensory tests were performed to reveal the best formulation of guava jam slice and the Bayes method used to determine the optimization of the selected formula. Based on the results of formulation and analysis, it was obtained that the guava jam slice with Acidulant concentration (0.02%, 0.04%, 0.06%), sucrose (70%, 80%, 90%, 100%) and agar powder (0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%) had pH 3.63-3.90, sugar content 34.68 g/100 g – 35.76 g/100 g, color intensity L*, a*, b* with ΔE* value was 37,88-53,97, fiber content 1.01%-1.59%, and water activity 0.852-0.893. Rheology properties for texture profile (hardness, cohesiveness, springiness, adhesive force, and gumminess) also showed significant value with agar powder formulation. Based on the Bayes test and hedonic test, it was found that the best formula was for guava jam slices with the addition of 90% sucrose, citric acid 0.04% and agar powder 0.9%. From the best formula, it was found the shelf life prediction model of Arrhenius formula was ln k = 20.222-6660.6(1/T) and the nutrition facts contribute total energy 45 kcal, fat 0%, carbohydrate 9%, protein 2% and dietary fiber 3%.

To characterize 20 genotypes of Psidium spp., observations were recorded for leaf blade length and width, petiole length, vein number, leaf surface area, leaf shape, leaf apex and base shape, upper and lower leaf surface colour, leaves colour during winters, leaf texture, pubescence and leaf lamina thickness which revealed significant variations among genotypes. Psidium chinensis was most diverse morphologically. Out of 20 decamer RAPD primers used four primers generated strong amplifications and resulted in polymorphic products; these were viz., OPA-03, OPA-05, OPS-04 and OPS-08. Percent polymorphism was 97.43% having a range of 87.5% to 100%. The average number of scoreable bands per primer was 9.75, while average number of polymorphic bands was 9.5. High polymorphism frequency was detected with all the selected primers. The similarity coefficient ranged from 0.42-0.83. The study showed that the genetic base of Indian guava can be rated as moderate to high diversity.

Abstract: The desertification is very huge problem in the dry land region of world
and compromising the agricultural development. Aspired by these factors, could
come from the use of synthetic material with superior water absorption and retention
capacity under thigh pressure and temperature to produce the Superabsorbent
polymers (SAP’s). The present research aimed to the establishment of biodegradable
Nanohydrogels for sustainable to the wild plantation of and cultivation of guava in
the different soil fields and also evaluated the various factors such as growth of plant,
leaves and stems elongation, micro elements supplementation and its wastage
reduction were examined and evaluated. The present research findings have revealed
that the guava plant has shown enhancing in size of the leave is by the application of
Nanohydrogels Nbp-1 enhances the growth of leaves and elongation of stem.
Keywords: Nanohydrogels Nbp-1, Biodegradation, Superabsorbent polymers,
Nanoclay, Water retention, water absorbency, Guava, Stem elongation, leaves and
growth of the plant.

The present experiment was carried out at Horticulture Research Centre, Patharchatta,
Department of Horticulture, GBPUA&T, Pantnagar, India under high density planting of
guava cv. Pant Prabhat. The study was conducted to find out the interaction effect of
pruning severity and plant spacing on growth, yield and profit. The treatments consisted of
two plant spacing and seven pruning severity viz., One leaf pair shoot pruning (P1,
OLP:);Two leaf pairs shoot pruning (P2, TLP); Three leaf pairs shoot pruning (P3, THLP);
Thinning out of non-fruiting shoots + One leaf pair shoot pruning (P4, TNFS+OLP);
Thinning out of non-fruiting shoots + Two leaf pairs shoot pruning (P5, TNFS+TLP);
Thinning out of non-fruiting shoots + Three leaf pairs shoot pruning (P6, TNFS+THLP);
Thinning out of non-fruiting shoots only (P7, TNFS) and no pruning (P0) as control. In this
way there were eight treatments with sixteen combinations replicated four times each with
two plants in one experimental unit. The annual increase in plant height, plant spread and
plant volume were found maximum in unpruned plants (P0), while, the stem diameter was
found maximum with treatment P4 (TNFS+OLP). The pruning severity had significantly
decreased the per cent fruit set for rainy season crop and subsequently increased the per
cent fruit set for winter season crop. The higher fruit yield was obtained with treatment P4
(TNFS+OLP) followed by treatment P1 (OLP). The unpruned plants (PO) produced lowest
fruit yield in winter season. The highest benefit: cost ratio was calculated with the
treatment P4 (TNFS+OLP) and 2.0 x 1.0 m plant spacing. Hence, for achieving higher
winter season crop with maximum profit under high density plantation of guava, complete
removal of non-fruiting shoots followed by one leaf pair shoot pruning of current seasons
growth should be done during first week of May.

Foliar application of nutrients enhances efficient use along with quick response. The experiment was undertaken to study the effect of foliar application of mineral nutrients viz., boron (B), zinc (Zn), calcium (Ca), and potassium (K) sprayed at different growth stages viz., at fruit set and at two weeks after fruit set of guava (Psidium guajava L.). Increase in plant canopy and minimum seed index was in Zn (0.03%) sprayed at fruit set. Fruit size, sugar: acid, and organoleptic score were better in K (0.5%) sprayed at two weeks after fruit set. Increased yield in Zn (0.01%) and pectin enhancement with B (0.03%) was found at two weeks after fruit set, respectively. Minimum physiological loss in weight of fruits was with Ca (0.5%) sprayed at two weeks after fruit set. In general, for most of the desirable characters 0.5% potassium (K) spray at 2 weeks after fruit set had better results.

RESUMEN: La mosquita blanca lanuda, Aleurothrixus floccosus (Maskell), es una plaga potencial de los cítricos en el Estado de Tamaulipas, México. Se colectaron ramitas y hojas infestadas con la plaga en Citrus spp. y Psidium guajava L. en varias localidades de la entidad y se identificaron sus avispas parasitoides. Se incluye la sinopsis de las 10 especies que proveen control natural de esta plaga.
ABSTRACT: Woolly whitefly, Aleurothrixus floccosus (Maskell), is a potential pest of citrus crops in the State of Tamaulipas, Mexico. Infested shoots and leaves of Citrus spp. and Psidium guajava L. were collected in several localities of the state and its parasitoids wasps were identified. Synopsis of the 10 species giving natural control of this pest is included.