Protein hydrolysates from two forms of salmon frames named “chunk” and “mince” were produced and characterized. Both samples were subjected to hydrolysis using alcalase and papain at 1%–3% (w/w protein) for 0–240 min. Hydrolysate prepared with either protease at 3% for 180 min had the solid yield of 24.05%–26.39%. Hydrolysates contained 79.20%–82.01% proteins, 6.03%–6.34% fat, 9.81%–11.09% ash, and 4.02%–5.80% moisture. Amino acid profile showed that all hydrolysates had glutamic acid/glutamine (113.45–117.56 mg/g sample), glycine (77.86–86.18 mg/g sample), aspartic acid/asparagine (76.04–78.67 mg/g sample), lysine (61.97–65.99 mg/g sample), and leucine (54.30–57.31 mg/g sample) as the predominant amino acids. The size distributions determined by gel filtration chromatography varied, depending on proteases and the form of frame used for the hydrolysis. Different hydrolysates showed varying antioxidant capacities. Thus, protein hydrolysates from salmon frame could be used as a nutritive supplement in the protein deficient foods. Practical applications Frames of salmon are by‐products from salmon fish processing industries. The frames contained the remaining meat, hence they can be used for the preparation of protein hydrolysates. Generally, hydrolysates from fish by‐products have been regarded as a promising food supplement, because they are rich in amino acids. Additionally, hydrolysates possess antioxidant activity, which is of health benefit. To produce the hydrolysate with less time consumption, the use of frame chunk instead of minced frame can be of better choice. Thus, frame of salmon, especially in chunk form, could be used as a raw material for production of protein hydrolysate using alcalase. The hydrolysate produced from salmon frame could serve as an alternative nutritive supplement to tackle the nutrition inadequacies in foods.

Fish processing by‐products often generated as discard can enzymatically be processed into a product known as fish protein hydrolysates (FPH). FPH is a good source of amino acid and peptides with bioactivities. FPH can be added to foods to improve nutritive values and bioactivities. However, bitterness in FPH, associated with hydrophobicity, degree of hydrolysis, molecular weight, proline residues, type of enzymes, and amino acid sequences has limited its uses in foods. Thus, FPH is used in foods at low levels. Numerous procedures such as extraction with alcohol, activated carbon treatment, Maillard reaction, cyclodextrin, chromatographic separation, and enzymatic hydrolysis with exopeptidase and plastein reaction have been explored to remove the bitterness of FPH. These methods can lower bitterness and improve its taste. However, changes in structure and loss of some peptides may occur. FPH with less or no bitterness can therefore be used at higher levels to alleviate nutrition deficiencies in foods. Practical applications Fish protein hydrolysate (FPH) is a nutritive ingredient, which can be produced from fish processing by‐products. However, bitterness in FPH has limited its potential use as a nutritive ingredient. As a result, it is incorporated into foods at low levels. Nevertheless, application of several reported debittering processes could assist to solve the problem of bitterness in FPH. The debittering can improve sensory property of FPH, thus widening its utilization.

Protein hydrolysates were obtained from salmon frame using Alcalase or Flavourzyme at 3% (w/w protein) for 180 min. Protein hydrolysates prepared using Alcalase (HA) and Flavourzyme (HF) had DH and yield of 25.1-26.9% and 28.5-32.3 g/100 g sample, respectively. HF showed lower bitterness score (5.78) than that of HA (8.68) (P \ 0.05). When HA and HF were further subjected to debittering with 2-butanol or isopropanol, the recovery of 77.88-81.60% was obtained (P \ 0.05). HF and HA debittered with 2-butanol possessed less bitterness score, 3.60 and 3.77, respectively (P \ 0.05). Surface hydrophobicity of 81.4 and 124.8 was attained when HF and HA were debittered with 2-butanol (P \ 0.05). Selected debittered hydrolysates, produced using Flavourzyme, followed by fractionation using 2-butanol (HF-B) contained glutamic acid/glutamine (15.14 g/100 g), aspartic acid/asparagine (10.07 g/100 g) and glycine (9.30 g/100 g) as the predominant amino acids. HF-B had the decreased ABTS radical scavenging activity and metal chelating activity. A 280 of peptides separated by gel filtration was lowered to some extent and coincided with the lower bitterness score and surface hydrophobicity. Thus, debittered protein hydrolysate from salmon frame could serve as a nutritive ingredient at high levels in health promoting foods.

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Alkaline treatment has been extensively implemented in the extraction process of hydroxyapatite (HAp) extraction from various kinds of bio-materials, such as animal bone and scales. The main purpose of such treatment is to remove proteinaceous substances from raw materials. The influence of the alkaline treatment that could alter not only the organic contents but also chemical composition—specifically the Ca/P mole ratios of bio-calcium, HAp, and the biphasic apatite powders derived from salmon bone, a by-product from the salmon industry—was investigated. Both HAp and biphasic apatite powders were obtained from the calcination of bio-calcium powders with and without alkaline treatment, respectively. An X-ray diffraction analysis confirmed the presence of hydroxyapatite and β-tricalcium phosphate (β-TCP) in the calcined bone powder without alkaline treatment while only a single phase of hydroxyapatite was observed in the alkaline-treated sample. Calcium and phosphorus contents were measured by an inductively coupled plasma optical emission spectrometer (ICP-OES). A variation of Ca/P ratios was observed among all samples, depending on the chemical and heat treatment conditions. Organic molecules, such as protein, fat, hydroxyproline, and TBARS, were significantly lowered in bio-calcium powders with the alkaline treatment. This work represents important research on chemical treatment prior to the raw material conversion process, which significantly influences chemical and phase compositions of the bio-calcium and hydroxyapatite powder derived from salmon bone waste.

Consumption of less phytonutrient foods has shown to cause different chronic diseases, despite over 50,000 edible plant breed available in various countries around the globe. These edible plants consist of seeds that can be consumed which possessed high health benefits. Moreover, nutritive values such as phytochemicals of edible seeds increased after germination. Therefore, germination has been reported to enhance various bioactive compounds such as γ-amino butyric acid, polyphenols, and vitamins which lead to greater bioactivity such as anti-diabetic, anti-bacteria, and anti-cancer effects when these seeds are consumed. Consequently, germination can be regarded as a cheap and effective way to enhance the nutritional value of edible seeds.

Objectives This study aimed to develop whole wheat crackers fortified with biocalcium (BC) and protein hydrolysate (PH) powders from salmon frame at varying substitution levels. Materials and Methods Whole wheat cracker fortified with BC and protein hydrolysate PH powders from salmon frame was produced. BC and PH powders or their mixtures at different ratios (3:1, 1:1, 1:3) were used to fortify the dough mix at a substitution level of 16.67% based on the whole wheat flour content. The physical, textural, sensory, and nutritional profiles of the crackers produced were examined and compared with crackers without fortification. Results The weight, colour, textural properties, and thickness of the crackers varied with the addition of different ratios of BC and PH powders. The incorporation of BC/PH at ratio (3:1) showed no negative effect on sensory properties. The crackers thus produced possessed higher protein, fat, calcium, phosphorus, sodium, and cholesterol but lower carbohydrate, sugar, fibre, and energy value than the control crackers without fortification. The crackers contained 0.026–0.045 mg/100 g polyunsaturated fatty acid. Developed crackers had a denser structure and were less porous than the control crackers as shown in scanning electron microscopic images. In scanning electron microscopy-energy dispersive X-ray spectroscopic (SEM-EDX) analysis, the crackers fortified with BC/PH at ratio (3:1) had higher calcium and phosphorus contents and intensity than the control. Conclusions This study demonstrated that the addition of BC and PH powders obtained from salmon frame represent a promising means of increasing the nutritive values of crackers.

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