Coconut water is a highly nutritious liquid food which is a by-product of the desiccated coconut industry. Freeze concentration is the most suitable concentration method for coconut water since the low-temperature operation for concentration does not deteriorate the original quality of coconut water. Suspension freeze concentration (SFC) and progressive freeze concentration (PFC) are the available FC methods, and SFC is a complex and expensive method compared with PFC. PFC is a novel freeze concentration technique to concentrate liquid food by using a simple system. The limitation of PFC is the lower product yield than SFC, and to overcome the problem, the partial ice-melting technique can be used. A simple cylindrical apparatus was used for PFC which consists of a sample vessel, agitator system, and a cooling bath (at −23°C±2°C temperature). The final concentration of the liquid product was directly affected by the apparatus agitator speed and sample vessel dipping speed. PFC agitator speed of 290 rpm and dipping speed of 1.3 cm h-1 were reported as the optimum operating conditions to achieve the highest concentration for the PFC apparatus used in this study. Using optimized agitation speed and dipping speed, coconut water was concentrated up to Brix 8.5° from the initial concentration of Brix 3.5°. PFC coconut water achieved 73.56% of total yield, 2.42 of concentration ratio, 0.7° of ice phase concentration, and 0.08 of effective partition coefficient. The partial melting technique was successfully explored by recovering initial ice fractions with high solute concentrations, and the total yield was improved up to 80%.
Seaweeds are a rich source of health beneficial bioactive nutraceuticals and currently, they are under-utilised in Sri Lanka. Thus, this study is to get an idea about the possibility of utilising seaweed in Sri Lankan food industry. In the present study, elemental composition analysis of Ulva fasciata obtained from 3 locations Mirissa (5°56/40.5// N: 80°27/20.2// E), Point Dondra (5°55/45.7//N: 80°35/02.5// E) and Galle (6°02/01.1// N: 80°12/52.2// E) and red algae varieties Gracilaria edulis and Gracilaria sp. obtained from Kalpitiya (8°15/40.8// N: 79°46/33.9// E and 8°13/35.0// N: 79°43/34.8// E) respectively. The elemental analysis was carried using X-ray fluorescence (XRF) analyzer. The results revealed that the predominant mineral of U. fasciata obtained from the 3 locations and Gracilaria sp. as calcium. While the predominant mineral in G. edulis was potassium. All the 5 varieties have various concentrations of elements such as K, Ca, Mn, Fe, Cu and Zn. Significantly high lead content was observed in U. fasciata obtained from Point Dondra. The elemental compositions showed variations among the same species obtained from different locations. The results also revealed that seaweed is a good source of certain essential and trace minerals. Keywords: Ulva fasciata, Gracilaria edulis, Gracilaria sp., minerals, seaweeds
Accumulation of non-biodegradable plastics is causing high levels of
environmental pollution. Currently, edible and biodegradable films and coatings for
food and nutraceutical applications are a fast emerging technology with increased
attention among researchers and consumers, which acts as an alternative to these
synthetic plastics. Edible coatings are most commonly developed from polysaccharides
and proteins. Among polysaccharides, seaweed-based polysaccharides play a vital role.
These seaweed-based polysaccharides, which are utilized in the development of edible
coatings and films, include Agar, Alginate, and carrageenan. Alginates are extracted
from brown algae, while agar and carrageenan are extracted from red algae varieties.
These developed coatings and films are commonly applied to extend the shelf life and
maintain the desired quality level in food. These films or coatings can be applied to
foods such as fruits, vegetables, meat, poultry, seafood, and dairy products. They
improve the quality of the product by retarding moisture loss, reducing lipid oxidation
and discoloration, sealing in volatile flavors, and functioning as carriers of food
additives such as antimicrobial and antioxidant agents. This book chapter discusses the
application of seaweed-based biodegradable films and coatings for food and
nutraceuticals.
Seaweeds are a rich source of health beneficial bioactive nutraceuticals and currently they are under-utilized in Sri Lanka. In the present study, proximate analysis of seaweed varieties Chnoospora minima and Porphyra sp. obtained from Mirissa, Matara, Sri Lanka and Ulva fasciata was taken from Point Dondra Matara, Sri Lanka on June, 2018 were investigated. The moisture content, total fat content, protein content and ash content were determined according to the Official methods of Analysis by Association of Official Analytical Chemists after drying for 8h at 600 C. The results revealed that the moisture contents (%) of Chnoospora minima, Porphyra sp. and Ulva fasciata were 13.24 ± 0.20, 14.30 ± 0.14 and 18.11 ± 0.01 respectively. Total fat contents (%) of Chnoospora minima, Porphyra sp. and Ulva fasciata were 0.21 ± 0.11, 0.19 ± 0.03 and 0.28 ± 0.05 respectively. Protein contents (%) of Chnoospora minima, Porphyra sp. and Ulva fasciata were 13.70 ± 0.2, 21.14 ± 0.04 and 11.84 ± 0.1. Total ash contents (%) of Chnoospora minima, Porphyra sp. and Ulva fasciata were 17.20 ± 0.24, 5.40 ± 0.7 and 18.05 ± 0.21 respectively. Total carbohydrate content (%) was analyzed according to the Dubois method. Chnoospora minima, Porphyra sp. and Ulva fasciata showed total carbohydrate content (%) as 3.87 + 0.66, 20.59 ± 0.24 and 7.68 ± 1.16 respectively. Moreover, the sulphate content was analyzed according to the precipitate method. Chnoospora minima, Porphyra sp. and Ulva fasciata showed 1.45 ± 0.35, 2.75 ± 0.07 and 4.54 ± 0.06, sulfate contents (%) respectively. In conclusion, highest ash content which indicates a good mineral content was observed in Ulva fasciata and Chnoospora minima. Fibre, protein and carbohydrate contents are significantly different among the 3 samples. Highest fibre content was observed in Chnoospora minima. Highest protein and carbohydrate contents were observed in Porphyra sp. But there is no significant difference in fat contents among the three samples.
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